CONTACT DERMATITIS Martín Gracia Facultad de Medicina Universidad Nacional de Colombia. Dermatología.
DEFINICIÓN <ul><li>Alteración inflamatoria </li></ul><ul><ul><li>frecuente </li></ul></ul><ul><ul><li>Exposición a varios ...
DEFINICIÓN <ul><li>Presentación clínica </li></ul><ul><ul><li>Vesículas y bullas localizadas sobre una piel eritematosa  ...
DEFINICIÓN <ul><li>Tratamiento </li></ul><ul><ul><ul><li>eliminación – agente </li></ul></ul></ul><ul><ul><ul><li>uso de c...
Eczema de contacto o dermatitis de contacto alérgica <ul><li>Eritema </li></ul>
Eczema de contacto o dermatitis de contacto alérgica; fotodermatitis de contacto  <ul><li>Eritema, excoriación, descamació...
Eczema de contacto o dermatitis de contacto alérgica <ul><li>Eritema, excoriación, liquenificación y costras </li></ul>
Eczema de contacto o dermatitis de contacto alérgica <ul><li>Eritema, fisuras y descamación </li></ul>
Eczema de contacto o dermatitis de contacto alérgica <ul><li>Eritema y costras </li></ul>
fotodermatitis de contacto (reacción de tipo IV) <ul><li>Eritema, hinchazón y vesículas </li></ul>
Dermatitis de contacto irritativa (de causa no alérgica) <ul><li>Eritema, edema, ampollas </li></ul>
Dermatitis de contacto irritativa (de causa no alérgica) <ul><li>Eritema, edema, ampollas, vesiculas, hinchazón </li></ul>
Dermatitis de contacto irritativa (de causa no alérgica) <ul><li>Descamación, erosiones, escoriaciones, costras </li></ul>
Dermatitis de contacto irritativa (de causa no alérgica) <ul><li>Eritema, vesiculas, descamación y edema </li></ul>
Epidemiology <ul><li>the most common occupational disease in the United States </li></ul><ul><li>90%    skin disorders  ...
Epidemiology <ul><li>Allergic contact dermatitis (ACD) does occur in children and infants </li></ul>
Allergic versus irritant contact dermatitis <ul><li>Distinguishing    allergic and irritant triggers </li></ul><ul><ul><l...
Allergic versus irritant contact dermatitis <ul><li>Both forms of contact dermatitis involve an inflammatory pathway </li>...
Allergic versus irritant contact dermatitis <ul><li>FR </li></ul><ul><li>Physical conditions </li></ul><ul><ul><li>Heat </...
Allergic versus irritant contact dermatitis <ul><li>Atopic persons </li></ul><ul><ul><li>Greater susceptibility ICD </li><...
Dermatitis de contacto alérgica <ul><li>Sensitization (afferent phase) </li></ul><ul><li>Most allergic diseases    immedi...
Dermatitis de contacto alérgica <ul><li>Haptens </li></ul><ul><li>Contact allergens    Covalently bond with tissue protei...
Dermatitis de contacto alérgica <ul><li>Haptens </li></ul><ul><li>Within the epidermis </li></ul><ul><ul><li>Pinocytosis b...
Dermatitis de contacto alérgica <ul><li>Langerhans cells </li></ul><ul><ul><li>migrate    regional draining lymph nodes <...
Dermatitis de contacto alérgica <ul><li>New peptides </li></ul><ul><li>Specific T-cell receptor </li></ul><ul><li>major hi...
Dermatitis de contacto alérgica <ul><li>Successful allergen presentation </li></ul><ul><ul><li>Langerhans cells    interl...
Dermatitis de contacto alérgica <ul><li>Patient’s initial contact </li></ul><ul><ul><li>Number of responding Th1 cells is ...
Dermatitis de contacto alérgica <ul><li>Elicitation (efferent phase) </li></ul><ul><li>Specific memory Th1 cells – circula...
Dermatitis de contacto alérgica <ul><li>Th1 cells </li></ul><ul><ul><li>release inflammatory cytokines </li></ul></ul><ul>...
Dermatitis de contacto alérgica <ul><li>Culmination </li></ul><ul><ul><li>epidermal spongiosis (intercellular edema) </li>...
Dermatitis de contacto alérgica <ul><li>Latency period </li></ul><ul><ul><li>From allergen contact to clinical dermatitis ...
Clinical features <ul><li>History </li></ul><ul><li>Detailed </li></ul><ul><li>Hidden sources of contact allergens </li></...
Clinical features <ul><li>Temporal relationship - days off and return to work  </li></ul><ul><ul><li>recent exposures </li...
Clinical features <ul><li>Exposures ≠ workplace </li></ul><ul><ul><li>Jewelry </li></ul></ul><ul><ul><li>Clothing </li></u...
Clinical features <ul><li>One uniformly present feature of ACD is </li></ul><ul><li>PRURITUS </li></ul><ul><li>without whi...
Physical examination <ul><li>Appearance - lesion in ACD </li></ul><ul><ul><li>corresponds -  stage at which the patient pr...
Physical examination <ul><li>Acute stage </li></ul><ul><ul><li>Marked erythema </li></ul></ul><ul><ul><li>Edema </li></ul>...
Physical examination <ul><ul><li>Vesicles </li></ul></ul><ul><ul><ul><li>Multiple </li></ul></ul></ul><ul><ul><ul><li>Seve...
Physical examination <ul><ul><li>vesicular fluid </li></ul></ul><ul><ul><ul><li>does not contain appreciable amounts of th...
Physical examination <ul><ul><li>chronic stage </li></ul></ul><ul><ul><ul><li>Papulovesicular lesions disappear </li></ul>...
Differential diagnosis <ul><ul><li>the physician’s clinical suspicion of ACD may be quite(bastante) high </li></ul></ul><u...
Differential diagnosis <ul><ul><li>Atopic dermatitis </li></ul></ul><ul><ul><ul><li>onset in infancy </li></ul></ul></ul><...
Differential diagnosis <ul><ul><li>Atopic dermatitis </li></ul></ul>
Differential diagnosis <ul><ul><li>seborrheic dermatitis </li></ul></ul><ul><ul><ul><li>predilection for </li></ul></ul></...
Differential diagnosis <ul><ul><li>seborrheic dermatitis </li></ul></ul>
Differential diagnosis <ul><ul><li>endogenous dermatoses </li></ul></ul><ul><ul><ul><li>More intensely pruritic eruptions ...
Differential diagnosis <ul><ul><li>endogenous dermatoses </li></ul></ul><ul><ul><ul><li>Nummular dermatitis </li></ul></ul...
Differential diagnosis <ul><ul><li>endogenous dermatoses </li></ul></ul><ul><ul><ul><li>Dyshidrotic dermatitis </li></ul><...
Differential diagnosis <ul><ul><li>Photocontact dermatitis </li></ul></ul><ul><ul><ul><li>Interaction </li></ul></ul></ul>...
Differential diagnosis <ul><ul><li>Photocontact dermatitis </li></ul></ul><ul><ul><ul><li>Clinically </li></ul></ul></ul><...
Differential diagnosis <ul><li>phototoxic reactions ↔ ICD subset </li></ul><ul><li>photoallergic reactions ↔ACD subset </l...
Differential diagnosis <ul><ul><li>phototoxic reaction </li></ul></ul><ul><ul><ul><li>Macular </li></ul></ul></ul><ul><ul>...
Differential diagnosis <ul><ul><li>photoallergic reaction </li></ul></ul><ul><ul><ul><li>delayed hypersensitivity reaction...
Differential diagnosis <ul><ul><li>two types of contact urticaria    subsets of contact dermatitis </li></ul></ul>
Differential diagnosis <ul><ul><ul><li>nonallergic form </li></ul></ul></ul><ul><ul><ul><ul><li>urticaria remains localize...
Differential diagnosis <ul><ul><ul><li>Allergic contact urticaria </li></ul></ul></ul><ul><ul><ul><ul><li>IgE-mediated mas...
Differential diagnosis <ul><ul><ul><li>Both forms of contact urticaria resemble noncontact urticaria </li></ul></ul></ul><...
Differential diagnosis <ul><ul><ul><li>Both forms of contact urticaria resemble noncontact urticaria </li></ul></ul></ul><...
Differential diagnosis <ul><li>Skin infections    strongly considered - immunocompromised patients </li></ul><ul><ul><li>...
Differential diagnosis <ul><li>Dermatophytic or tinea </li></ul><ul><ul><li>Dry </li></ul></ul><ul><ul><li>scaling erythem...
Differential diagnosis <ul><li>infections present vesicular lesions </li></ul><ul><ul><li>herpes simplex virus </li></ul><...
Differential diagnosis <ul><li>varicella zoster virus </li></ul><ul><ul><ul><li>primary varicella </li></ul></ul></ul><ul>...
Differential diagnosis <ul><li>varicella reactivated </li></ul><ul><ul><ul><li>few constitutional symptoms </li></ul></ul>...
Differential diagnosis <ul><li>Impetigo </li></ul><ul><ul><li>all age groups, but is usually seen in  young children </li>...
Differential diagnosis <ul><li>Impetigo </li></ul>
Differential diagnosis <ul><li>psoriasis  </li></ul><ul><ul><li>thick(espeso) silver - scaled plaques </li></ul></ul><ul><...
Differential diagnosis <ul><li>psoriasis  </li></ul><ul><ul><li>thick(espeso) silver - scaled plaques </li></ul></ul><ul><...
Differential diagnosis <ul><li>*biopsy </li></ul><ul><ul><li>low utility in ACD  </li></ul></ul><ul><ul><ul><li>histologic...
Anatomic approach <ul><li>Exposure to the suspect allergen - congruent - distribution of the eruption </li></ul><ul><li>mo...
Anatomic approach <ul><li>Head and neck </li></ul><ul><li>Scalp  have greater resistance than    face, ears, and neck </l...
Anatomic approach <ul><li>Head and neck </li></ul><ul><li>common triggers </li></ul><ul><ul><li>Metals from jewelry pierci...
Anatomic approach <ul><li>Neck </li></ul><ul><ul><li>cosmetics and fragrances </li></ul></ul><ul><ul><li>metals </li></ul>...
Anatomic approach <ul><li>Extremities </li></ul><ul><li>50% involve the hands </li></ul><ul><ul><li>supposed innocuous ite...
Anatomic approach <ul><li>Extremities </li></ul><ul><ul><li>ƒ dorsal side of the hands </li></ul></ul><ul><ul><ul><li>the ...
Anatomic approach <ul><li>Extremities </li></ul><ul><ul><ul><li>photosensitive process </li></ul></ul></ul><ul><ul><ul><ul...
Anatomic approach <ul><li>Extremities </li></ul><ul><ul><li>Stasis dermatitis - lower legs - chronic varicose inflammation...
Anatomic approach <ul><li>Torso and groin(ingle) </li></ul><ul><li>Fragrances - deodorants - axillary vault </li></ul><ul>...
Anatomic approach <ul><li>Torso and groin(ingle) </li></ul><ul><li>Incontinent    bed – bound(obligados) patients - urine...
Anatomic approach <ul><li>Oral mucosa </li></ul><ul><li>Langerhans cells are sparse(escasas) at mucosal sites </li></ul><u...
Anatomic approach <ul><li>Oral mucosa </li></ul><ul><ul><li>saliva - buffering and diluting effect on the allergen </li></...
Anatomic approach <ul><li>Systemic involvement </li></ul><ul><li>Systemic ACD - form of autoeczematization - known as an ‘...
Anatomic approach <ul><li>Systemic involvement    ‘‘id reaction.’’ </li></ul><ul><li>Generalized eruption - result - hema...
Allergens   <ul><li>Poison ivy </li></ul><ul><ul><li>specie: Toxicodendron genus  </li></ul></ul><ul><ul><li>plant family:...
Allergens <ul><li>Poison ivy </li></ul><ul><ul><li>United States - responsible -more cases – ACD </li></ul></ul><ul><ul><l...
Allergens <ul><li>Poison ivy </li></ul><ul><ul><li>chronicity and spread(propagación) of symptoms </li></ul></ul><ul><ul><...
Allergens <ul><li>Metals </li></ul><ul><li>Nickel </li></ul><ul><ul><li>most common metal allergen </li></ul></ul><ul><ul>...
Allergens <ul><li>Metals </li></ul><ul><li>Sensitivity to aluminum is quite uncommon </li></ul><ul><ul><li>substitution wi...
Allergens <ul><li>Medications </li></ul><ul><li>Topical antibiotics </li></ul><ul><ul><li>> ƒ neomycin and bacitracin </li...
Allergens <ul><li>Medications </li></ul><ul><li>Topical corticosteroids </li></ul><ul><ul><li>structure may be altered to ...
Allergens <ul><li>Medications </li></ul><ul><li>Ethylenediamine </li></ul><ul><ul><li>Common allergenic  preservative </li...
Allergens <ul><li>Medications </li></ul><ul><li>thimerosal </li></ul><ul><ul><li>Preservative with the highest prevalence ...
Allergens <ul><li>Latex and rubber(caucho) chemicals </li></ul><ul><li>Latex fluid - Brazilian rubber tree - Hevea brasili...
Allergens <ul><li>Latex and rubber(caucho) chemicals </li></ul><ul><li>Immediate hypersensitivity reactions  </li></ul><ul...
Allergens <ul><li>Latex and rubber(caucho) chemicals </li></ul><ul><li>*airborne(aera) exposure proteins-Latex </li></ul><...
Allergens <ul><li>Formaldehyde </li></ul><ul><li>Formaldehyde itself </li></ul><ul><li>formaldehyde–releasers = quaternium...
Allergens <ul><li>Fragrances </li></ul><ul><ul><ul><li>Cosmetics </li></ul></ul></ul><ul><ul><ul><li>Fabrics </li></ul></u...
Allergens <ul><li>Fragrances </li></ul><ul><ul><li>Balsam of Peru >ƒ ACD - nonallergic contact urticaria </li></ul></ul><u...
Patch testing <ul><li>gold standard – Dx ACD </li></ul><ul><li>first use  </li></ul><ul><ul><li>1895 </li></ul></ul><ul><u...
Patch testing <ul><li>Standardized allergens- delivery vehicles </li></ul><ul><li>ACD eruption    appears - 2 to 3 days o...
Patch testing <ul><li>Screening panels - 20 to 30 - most prevalent allergens </li></ul><ul><ul><li>>ƒ TRUE Test (Mekos Lab...
Patch testing <ul><li>*Another option    assortments(diversidad) of allergens </li></ul><ul><li>Filter paper in 8-mm alum...
Patch testing <ul><li>Techniques </li></ul><ul><li>Applied Allergens together </li></ul><ul><li>hairless region </li></ul>...
Patch testing <ul><li>Techniques </li></ul><ul><li>An adhesive keeps the allergens secured </li></ul><ul><li>Edges(bordes)...
Patch testing <ul><li>Techniques </li></ul><ul><li>longer allergic response </li></ul><ul><ul><li>Elderly patients </li></...
Patch testing <ul><li>Precautions </li></ul><ul><li>Not be performed in - acute or widespread(extendida) contact dermatiti...
Patch testing <ul><li>to consider </li></ul><ul><li>bacitracin and gold are not TRUE Test panels    prevalent  allergens ...
Patch testing <ul><li>to consider </li></ul><ul><li>bacitracin and gold are not TRUE Test panels    prevalent  allergens ...
MANAGEMENT <ul><li>treating the active case </li></ul><ul><li>Prevention </li></ul><ul><li>treatment </li></ul><ul><ul><li...
MANAGEMENT
MANAGEMENT
MANAGEMENT
MANAGEMENT <ul><li>PREVENTION </li></ul><ul><li>workplace    eliminating harmful exposures </li></ul><ul><ul><li>substitu...
MANAGEMENT <ul><li>correct selection of gloves </li></ul><ul><ul><li>Cotton gloves </li></ul></ul><ul><ul><ul><li>allow th...
MANAGEMENT <ul><li>Barrier creams </li></ul><ul><ul><li>questionable value in protecting against contact with irritants </...
MANAGEMENT <ul><li>PRE-EMPLOYMENT SCREENING </li></ul><ul><ul><li>predisposing factors </li></ul></ul><ul><ul><ul><li>Atop...
MANAGEMENT <ul><li>WORK RELATED EDUCATIONAL PROGRAMMES </li></ul><ul><ul><li>Half    OCDs    appear    first two years ...
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Contact dermatitis

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Transcript of "Contact dermatitis"

  1. 1. CONTACT DERMATITIS Martín Gracia Facultad de Medicina Universidad Nacional de Colombia. Dermatología.
  2. 2. DEFINICIÓN <ul><li>Alteración inflamatoria </li></ul><ul><ul><li>frecuente </li></ul></ul><ul><ul><li>Exposición a varios antígenos e irritantes </li></ul></ul><ul><li>Mecanismos  distintos tipos </li></ul><ul><ul><li>Eczema de contacto o dermatitis de contacto alérgica (reacción de hipersensibilidad de tipo IV) </li></ul></ul><ul><ul><li>Dermatitis de contacto irritativa (de causa no alérgica) </li></ul></ul><ul><ul><li>Fotodermatitis de contacto (reacción de tipo IV) </li></ul></ul><ul><ul><li>Urticaria de contacto (reacción de hipersensibilidad de tipo I) </li></ul></ul>
  3. 3. DEFINICIÓN <ul><li>Presentación clínica </li></ul><ul><ul><li>Vesículas y bullas localizadas sobre una piel eritematosa  estadios agudos </li></ul></ul><ul><ul><li>Placas eritematosas liquenificadas  estadios crónicos </li></ul></ul><ul><li>Diagnóstico </li></ul><ul><ul><li>Localización – erupción </li></ul></ul><ul><ul><li>Historia – exposición </li></ul></ul><ul><ul><li>Pruebas epicutáneas - aplicación alergeno producirá inflamación </li></ul></ul>
  4. 4. DEFINICIÓN <ul><li>Tratamiento </li></ul><ul><ul><ul><li>eliminación – agente </li></ul></ul></ul><ul><ul><ul><li>uso de cremas esteroides antiinflamatorias </li></ul></ul></ul><ul><ul><ul><li>antihistamínicos </li></ul></ul></ul><ul><ul><li>casos graves </li></ul></ul><ul><ul><ul><li>corticosteroides orales </li></ul></ul></ul>
  5. 5. Eczema de contacto o dermatitis de contacto alérgica <ul><li>Eritema </li></ul>
  6. 6. Eczema de contacto o dermatitis de contacto alérgica; fotodermatitis de contacto <ul><li>Eritema, excoriación, descamación, liquenificación y edema </li></ul>
  7. 7. Eczema de contacto o dermatitis de contacto alérgica <ul><li>Eritema, excoriación, liquenificación y costras </li></ul>
  8. 8. Eczema de contacto o dermatitis de contacto alérgica <ul><li>Eritema, fisuras y descamación </li></ul>
  9. 9. Eczema de contacto o dermatitis de contacto alérgica <ul><li>Eritema y costras </li></ul>
  10. 10. fotodermatitis de contacto (reacción de tipo IV) <ul><li>Eritema, hinchazón y vesículas </li></ul>
  11. 11. Dermatitis de contacto irritativa (de causa no alérgica) <ul><li>Eritema, edema, ampollas </li></ul>
  12. 12. Dermatitis de contacto irritativa (de causa no alérgica) <ul><li>Eritema, edema, ampollas, vesiculas, hinchazón </li></ul>
  13. 13. Dermatitis de contacto irritativa (de causa no alérgica) <ul><li>Descamación, erosiones, escoriaciones, costras </li></ul>
  14. 14. Dermatitis de contacto irritativa (de causa no alérgica) <ul><li>Eritema, vesiculas, descamación y edema </li></ul>
  15. 15. Epidemiology <ul><li>the most common occupational disease in the United States </li></ul><ul><li>90%  skin disorders  workplace </li></ul><ul><li>6 million chemicals </li></ul><ul><ul><li>3000 have been known to cause allergic contact dermatitis (ACD) </li></ul></ul><ul><ul><li>New chemical sensitizers are introduced </li></ul></ul><ul><ul><li>annual cost  $250 million </li></ul></ul><ul><ul><ul><li>Lost productivity </li></ul></ul></ul><ul><ul><ul><li>medical care </li></ul></ul></ul><ul><ul><ul><li>disability payments </li></ul></ul></ul>
  16. 16. Epidemiology <ul><li>Allergic contact dermatitis (ACD) does occur in children and infants </li></ul>
  17. 17. Allergic versus irritant contact dermatitis <ul><li>Distinguishing  allergic and irritant triggers </li></ul><ul><ul><li>Clinical and histologic examination </li></ul></ul>
  18. 18. Allergic versus irritant contact dermatitis <ul><li>Both forms of contact dermatitis involve an inflammatory pathway </li></ul><ul><ul><li>The reactions of ICD are nonimmunologic </li></ul></ul><ul><ul><ul><li>Direct epidermal keratinocyte damage </li></ul></ul></ul><ul><ul><ul><li>concentration  irritant  duration contact </li></ul></ul></ul><ul><ul><li>ACD </li></ul></ul><ul><ul><ul><li>Affects genetically susceptible persons </li></ul></ul></ul><ul><ul><ul><ul><li>Previously sensitized by allergen </li></ul></ul></ul></ul>
  19. 19. Allergic versus irritant contact dermatitis <ul><li>FR </li></ul><ul><li>Physical conditions </li></ul><ul><ul><li>Heat </li></ul></ul><ul><ul><li>Cold </li></ul></ul><ul><ul><li>repeated frictional exposure </li></ul></ul><ul><ul><li>Low humidity </li></ul></ul><ul><li>Prior damage – skin </li></ul><ul><ul><li>Dehydration </li></ul></ul><ul><ul><li>Trauma </li></ul></ul><ul><ul><li>Compromises – integrity - epidermal barrier (stratum corneum) </li></ul></ul><ul><li>*more vulnerable to irritants </li></ul>
  20. 20. Allergic versus irritant contact dermatitis <ul><li>Atopic persons </li></ul><ul><ul><li>Greater susceptibility ICD </li></ul></ul><ul><ul><ul><li>phenomenon caused by ‘‘itch - scratch cycle’’ of AC </li></ul></ul></ul><ul><ul><ul><ul><li>increased penetration of irritants  no allergens </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Tendency in atopy to favor pathways of the Th2  rather than the Th1 pathways of ACD </li></ul></ul></ul></ul>
  21. 21. Dermatitis de contacto alérgica <ul><li>Sensitization (afferent phase) </li></ul><ul><li>Most allergic diseases  immediate hypersensitivity response involving IgE </li></ul><ul><li>ACD  prototypic delayed (or cell-mediated) hypersensitivity reaction </li></ul><ul><li>Previously sensitized T-helper cells </li></ul>
  22. 22. Dermatitis de contacto alérgica <ul><li>Haptens </li></ul><ul><li>Contact allergens  Covalently bond with tissue proteins  immunogenic  initiate afferent phase </li></ul><ul><li>Degree of Th1 sensitization  proportional to stability  hapten-protein couplings </li></ul><ul><li>> chemically reactive haptens </li></ul><ul><ul><li>lipid-soluble </li></ul></ul><ul><ul><li>low-molecular-weight molecules </li></ul></ul><ul><ul><ul><li>easily penetrate the stratum corneum </li></ul></ul></ul><ul><ul><ul><li>strongly bind carrier proteins </li></ul></ul></ul>
  23. 23. Dermatitis de contacto alérgica <ul><li>Haptens </li></ul><ul><li>Within the epidermis </li></ul><ul><ul><li>Pinocytosis by Langerhans cells </li></ul></ul><ul><ul><ul><li>Degradation of the allergens </li></ul></ul></ul><ul><ul><ul><ul><li>Processed peptides </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Displayed - Langerhans cell surface  context - major histocompatibility complex class II molecules </li></ul></ul></ul></ul></ul>
  24. 24. Dermatitis de contacto alérgica <ul><li>Langerhans cells </li></ul><ul><ul><li>migrate  regional draining lymph nodes </li></ul></ul><ul><ul><ul><li>processed peptides are presented to naïve Th1 cells </li></ul></ul></ul>
  25. 25. Dermatitis de contacto alérgica <ul><li>New peptides </li></ul><ul><li>Specific T-cell receptor </li></ul><ul><li>major histocompatibility complex II molecules </li></ul><ul><ul><li>” found only on the Th1 cells of susceptible patients” </li></ul></ul><ul><li>*Those who have  necessary repertoire  receptor variable regions  genetically rearranged TR-cell </li></ul>
  26. 26. Dermatitis de contacto alérgica <ul><li>Successful allergen presentation </li></ul><ul><ul><li>Langerhans cells  interleukin-1 </li></ul></ul><ul><ul><li>Th1 cells  interleukin -2 </li></ul></ul><ul><ul><ul><li>Clonal proliferation  newly sensitized Th1 cells </li></ul></ul></ul><ul><ul><ul><ul><li>paracortical region of the lymph nodes </li></ul></ul></ul></ul>
  27. 27. Dermatitis de contacto alérgica <ul><li>Patient’s initial contact </li></ul><ul><ul><li>Number of responding Th1 cells is insufficient to a clinically response </li></ul></ul><ul><ul><li>But - Then - memory Th1 cells are released into the circulation </li></ul></ul>
  28. 28. Dermatitis de contacto alérgica <ul><li>Elicitation (efferent phase) </li></ul><ul><li>Specific memory Th1 cells – circulating </li></ul><ul><li>Langerhans cells  Allergen presentation  expanded pool of Th1 cells  occurs in: </li></ul><ul><ul><li>Epidermis </li></ul></ul><ul><ul><li>Dermis </li></ul></ul><ul><ul><li>Regional draining lymph nodes </li></ul></ul><ul><ul><ul><li>*Skin-specific homing receptors on the Th1 cells </li></ul></ul></ul>
  29. 29. Dermatitis de contacto alérgica <ul><li>Th1 cells </li></ul><ul><ul><li>release inflammatory cytokines </li></ul></ul><ul><ul><li>interferon-γ  chemotactic </li></ul></ul><ul><ul><ul><li>macrophages </li></ul></ul></ul><ul><ul><ul><li>cytotoxic T cells </li></ul></ul></ul><ul><ul><ul><li>Natural killer cells </li></ul></ul></ul><ul><ul><li>Granulocyte-macrophage colony–stimulating factor </li></ul></ul><ul><ul><ul><li>augments  bone marrow’s production </li></ul></ul></ul><ul><ul><ul><ul><li>Lymphocytes </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Granulocytes </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Monocytes </li></ul></ul></ul></ul>
  30. 30. Dermatitis de contacto alérgica <ul><li>Culmination </li></ul><ul><ul><li>epidermal spongiosis (intercellular edema) </li></ul></ul><ul><ul><li>dermal infiltrate </li></ul></ul><ul><ul><ul><li>*characteristic of ACD  Lymphocytic </li></ul></ul></ul>
  31. 31. Dermatitis de contacto alérgica <ul><li>Latency period </li></ul><ul><ul><li>From allergen contact to clinical dermatitis </li></ul></ul><ul><ul><ul><li>time for Langerhans cells to present the allergen </li></ul></ul></ul><ul><ul><ul><li>time for Th1 cells to </li></ul></ul></ul><ul><ul><ul><ul><li>proliferate </li></ul></ul></ul></ul><ul><ul><ul><ul><li>secrete cytokines </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Travel - site of contact </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Between 12 to 48 hours - previously sensitized person </li></ul></ul></ul></ul></ul>
  32. 32. Clinical features <ul><li>History </li></ul><ul><li>Detailed </li></ul><ul><li>Hidden sources of contact allergens </li></ul><ul><li>Occupational exposure - highest risk  </li></ul><ul><ul><li>food production </li></ul></ul><ul><ul><li>construction </li></ul></ul><ul><ul><li>printing </li></ul></ul><ul><ul><li>metal plating (enchapado en metal) </li></ul></ul><ul><ul><li>Machine tool operation (operarios de maquinas) </li></ul></ul><ul><ul><li>engine service (Mechanics) </li></ul></ul><ul><ul><li>leather work (trabajo del cuero) </li></ul></ul><ul><ul><li>health care </li></ul></ul><ul><ul><li>cosmetology </li></ul></ul><ul><ul><li>forestry </li></ul></ul>
  33. 33. Clinical features <ul><li>Temporal relationship - days off and return to work </li></ul><ul><ul><li>recent exposures </li></ul></ul><ul><ul><ul><li>Strong allergens  poison ivy </li></ul></ul></ul><ul><ul><ul><ul><li>Effect - hours – days </li></ul></ul></ul></ul><ul><ul><ul><ul><li>after - one exposure </li></ul></ul></ul></ul><ul><ul><li>long-term exposures > ƒ OACD </li></ul></ul><ul><ul><ul><li>Weak sensitizers  chromate </li></ul></ul></ul><ul><ul><ul><ul><li>require repeated exposures - months to years to develop sensitivity </li></ul></ul></ul></ul>
  34. 34. Clinical features <ul><li>Exposures ≠ workplace </li></ul><ul><ul><li>Jewelry </li></ul></ul><ul><ul><li>Clothing </li></ul></ul><ul><ul><li>Cosmetics </li></ul></ul><ul><ul><li>Fragrances </li></ul></ul><ul><ul><li>Soaps </li></ul></ul><ul><ul><li>Detergents </li></ul></ul><ul><ul><li>household cleaning agents </li></ul></ul><ul><ul><li>paints </li></ul></ul><ul><ul><li>resins </li></ul></ul><ul><ul><li>rubbers (caucho y gomas) </li></ul></ul><ul><ul><li>latex </li></ul></ul><ul><ul><li>adhesives </li></ul></ul><ul><ul><li>topical medicines </li></ul></ul>
  35. 35. Clinical features <ul><li>One uniformly present feature of ACD is </li></ul><ul><li>PRURITUS </li></ul><ul><li>without which the Dx of ACD is excluded </li></ul>
  36. 36. Physical examination <ul><li>Appearance - lesion in ACD </li></ul><ul><ul><li>corresponds - stage at which the patient presents. </li></ul></ul>
  37. 37. Physical examination <ul><li>Acute stage </li></ul><ul><ul><li>Marked erythema </li></ul></ul><ul><ul><li>Edema </li></ul></ul><ul><ul><li>Vesicle formation </li></ul></ul><ul><ul><li>Edema predominates if areas of loose(sueltas) tissue </li></ul></ul><ul><ul><ul><li>Eyelids </li></ul></ul></ul><ul><ul><ul><li>Genitalia </li></ul></ul></ul>
  38. 38. Physical examination <ul><ul><li>Vesicles </li></ul></ul><ul><ul><ul><li>Multiple </li></ul></ul></ul><ul><ul><ul><li>Severe </li></ul></ul></ul><ul><ul><ul><li>may coalesce into bullae </li></ul></ul></ul><ul><ul><ul><li>filled with a clear, transudative fluid </li></ul></ul></ul><ul><ul><ul><li>Rupture during the subacute stage </li></ul></ul></ul><ul><ul><ul><li>rupture  oozing(resumar) and eroded(erosion)  eczematous appearance </li></ul></ul></ul>
  39. 39. Physical examination <ul><ul><li>vesicular fluid </li></ul></ul><ul><ul><ul><li>does not contain appreciable amounts of the allergen </li></ul></ul></ul><ul><ul><ul><li>does not spread the eruption to other areas of the body or to other </li></ul></ul></ul><ul><ul><ul><li>may be replaced by papules </li></ul></ul></ul><ul><ul><li>Crustin(Costra) and scaling(descamación) soon become more prominent than the erythema and edema </li></ul></ul>
  40. 40. Physical examination <ul><ul><li>chronic stage </li></ul></ul><ul><ul><ul><li>Papulovesicular lesions disappear </li></ul></ul></ul><ul><ul><ul><li>Lichenification </li></ul></ul></ul><ul><ul><li>*The principles of prevention and treatment of ACD remain similar, regardless of the stage. </li></ul></ul>
  41. 41. Differential diagnosis <ul><ul><li>the physician’s clinical suspicion of ACD may be quite(bastante) high </li></ul></ul><ul><ul><li>It is paramount(importante)  consider - potentially more serious etiologies </li></ul></ul><ul><ul><li>ICD > ƒ confused </li></ul></ul><ul><ul><li>ƒ atopic dermatitis </li></ul></ul>
  42. 42. Differential diagnosis <ul><ul><li>Atopic dermatitis </li></ul></ul><ul><ul><ul><li>onset in infancy </li></ul></ul></ul><ul><ul><ul><li>ACD is uncommon in children younger than 8 years old </li></ul></ul></ul><ul><ul><ul><li>Dry skin and pruritus  prominent - before lesions appear - ≠ ACD  afterwards </li></ul></ul></ul><ul><ul><ul><li>Tends to be symmetrically distributed on extensor surfaces - on flexural surfaces </li></ul></ul></ul>
  43. 43. Differential diagnosis <ul><ul><li>Atopic dermatitis </li></ul></ul>
  44. 44. Differential diagnosis <ul><ul><li>seborrheic dermatitis </li></ul></ul><ul><ul><ul><li>predilection for </li></ul></ul></ul><ul><ul><ul><ul><li>eyebrows </li></ul></ul></ul></ul><ul><ul><ul><ul><li>nasal labial folds(pliegues naso-labiales) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>scalp (cuero cabelludo) </li></ul></ul></ul></ul><ul><ul><ul><li>Mild pruritus </li></ul></ul></ul><ul><ul><ul><li>Greasy(grasosa) or oily(oleosa) coating(capa) with scaly(descamación) </li></ul></ul></ul><ul><ul><ul><li>irregularly shaped(forma) erythema </li></ul></ul></ul>
  45. 45. Differential diagnosis <ul><ul><li>seborrheic dermatitis </li></ul></ul>
  46. 46. Differential diagnosis <ul><ul><li>endogenous dermatoses </li></ul></ul><ul><ul><ul><li>More intensely pruritic eruptions </li></ul></ul></ul><ul><ul><ul><li>Nummular dermatitis </li></ul></ul></ul><ul><ul><ul><ul><li>one or a group of coin – shaped </li></ul></ul></ul></ul><ul><ul><ul><ul><li>eczematous patches 2 to 10 cm in diameter </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Usually  torso and extremities  but not the head </li></ul></ul></ul></ul></ul><ul><ul><ul><li>Dyshidrotic dermatitis </li></ul></ul></ul><ul><ul><ul><ul><li>appears as multiple vesicles 1 to 2 mm in diameter </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>palms </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>soles </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>lateral aspects of the fingers and toes </li></ul></ul></ul></ul></ul>
  47. 47. Differential diagnosis <ul><ul><li>endogenous dermatoses </li></ul></ul><ul><ul><ul><li>Nummular dermatitis </li></ul></ul></ul>
  48. 48. Differential diagnosis <ul><ul><li>endogenous dermatoses </li></ul></ul><ul><ul><ul><li>Dyshidrotic dermatitis </li></ul></ul></ul>
  49. 49. Differential diagnosis <ul><ul><li>Photocontact dermatitis </li></ul></ul><ul><ul><ul><li>Interaction </li></ul></ul></ul><ul><ul><ul><ul><li>exogenous chemical  UV component of sunlight </li></ul></ul></ul></ul><ul><ul><ul><ul><li>recently ingested drug </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>sulfonamide </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Fluoroquinolone </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Tetracycline </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Oral contraceptive </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>nonsteroidal anti-inflammatory drug </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>topically applied substance - cold tar extract (extracto de alquitran frio) </li></ul></ul></ul></ul></ul>
  50. 50. Differential diagnosis <ul><ul><li>Photocontact dermatitis </li></ul></ul><ul><ul><ul><li>Clinically </li></ul></ul></ul><ul><ul><ul><ul><li>sun-exposed areas </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>face </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>arms </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>upper chest </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>is noticeably spared </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>skin under the chin - behind the ears - upper eyelids </li></ul></ul></ul></ul></ul>
  51. 51. Differential diagnosis <ul><li>phototoxic reactions ↔ ICD subset </li></ul><ul><li>photoallergic reactions ↔ACD subset </li></ul>
  52. 52. Differential diagnosis <ul><ul><li>phototoxic reaction </li></ul></ul><ul><ul><ul><li>Macular </li></ul></ul></ul><ul><ul><ul><ul><li>tender erythema </li></ul></ul></ul></ul><ul><ul><ul><li>can resemble(parecer) severe sunburn(quemaduras) </li></ul></ul></ul>
  53. 53. Differential diagnosis <ul><ul><li>photoallergic reaction </li></ul></ul><ul><ul><ul><li>delayed hypersensitivity reaction - induced by UV light  which chemically alters the sensitizing allergen in the skin. </li></ul></ul></ul><ul><ul><ul><ul><li>Pruritic </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Papulovesicular </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Eczematous </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>*similar to ACD </li></ul></ul></ul></ul></ul>
  54. 54. Differential diagnosis <ul><ul><li>two types of contact urticaria  subsets of contact dermatitis </li></ul></ul>
  55. 55. Differential diagnosis <ul><ul><ul><li>nonallergic form </li></ul></ul></ul><ul><ul><ul><ul><li>urticaria remains localized  site of contact - caused -direct cell mediator release from: </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>fragrances </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>food preservatives </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>insect stings </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>hairs </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>topical medicines </li></ul></ul></ul></ul></ul>
  56. 56. Differential diagnosis <ul><ul><ul><li>Allergic contact urticaria </li></ul></ul></ul><ul><ul><ul><ul><li>IgE-mediated mast cell stimulation </li></ul></ul></ul></ul><ul><ul><ul><ul><li>requires prior exposure to sensitizing allergens </li></ul></ul></ul></ul><ul><ul><ul><ul><li>foods </li></ul></ul></ul></ul><ul><ul><ul><ul><li>metals </li></ul></ul></ul></ul><ul><ul><ul><ul><li>animal saliva </li></ul></ul></ul></ul><ul><ul><ul><ul><li>latex </li></ul></ul></ul></ul><ul><ul><ul><ul><li>industrial products </li></ul></ul></ul></ul><ul><ul><ul><ul><li>topical medicines </li></ul></ul></ul></ul>
  57. 57. Differential diagnosis <ul><ul><ul><li>Both forms of contact urticaria resemble noncontact urticaria </li></ul></ul></ul><ul><ul><ul><li>classic wheal and flare response  appears within 30 minutes of exposure </li></ul></ul></ul><ul><ul><ul><li>allergic contact urticaria may become generalized </li></ul></ul></ul><ul><ul><ul><ul><li>angioedema or anaphylaxis </li></ul></ul></ul></ul><ul><ul><ul><li>Urticaria or angioedema - contact or noncontact - can be –mistaken(confundida) for ACD </li></ul></ul></ul><ul><ul><ul><ul><li>*when the eyelids are involved </li></ul></ul></ul></ul>
  58. 58. Differential diagnosis <ul><ul><ul><li>Both forms of contact urticaria resemble noncontact urticaria </li></ul></ul></ul><ul><ul><ul><li>classic wheal and flare response  appears within 30 minutes of exposure </li></ul></ul></ul><ul><ul><ul><li>allergic contact urticaria may become generalized </li></ul></ul></ul><ul><ul><ul><ul><li>angioedema or anaphylaxis </li></ul></ul></ul></ul><ul><ul><ul><li>Urticaria or angioedema - contact or noncontact - can be –mistaken(confundida) for ACD </li></ul></ul></ul><ul><ul><ul><ul><li>*when the eyelids are involved </li></ul></ul></ul></ul>
  59. 59. Differential diagnosis <ul><li>Skin infections  strongly considered - immunocompromised patients </li></ul><ul><ul><li>Cellulitis </li></ul></ul><ul><ul><ul><li>erythema and edema </li></ul></ul></ul><ul><ul><ul><li>Dx dif </li></ul></ul></ul><ul><ul><ul><ul><li>warmth </li></ul></ul></ul></ul><ul><ul><ul><ul><li>tenderness </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Trauma  common precipitant </li></ul></ul></ul></ul><ul><ul><ul><ul><li>fever and leukocytosis </li></ul></ul></ul></ul>
  60. 60. Differential diagnosis <ul><li>Dermatophytic or tinea </li></ul><ul><ul><li>Dry </li></ul></ul><ul><ul><li>scaling erythema </li></ul></ul><ul><ul><li>annular ring and central clearing </li></ul></ul><ul><ul><ul><li>Diagnosis  scraping scales  glass slide  adding potassium hydroxide  visualizing branching hyphae </li></ul></ul></ul>
  61. 61. Differential diagnosis <ul><li>infections present vesicular lesions </li></ul><ul><ul><li>herpes simplex virus </li></ul></ul><ul><ul><ul><li>tender </li></ul></ul></ul><ul><ul><ul><li>may umbilicate </li></ul></ul></ul><ul><ul><ul><li>predilection for perioral and genital regions </li></ul></ul></ul>
  62. 62. Differential diagnosis <ul><li>varicella zoster virus </li></ul><ul><ul><ul><li>primary varicella </li></ul></ul></ul><ul><ul><ul><ul><li>2- to 3-day prodrome of flu like symptoms </li></ul></ul></ul></ul><ul><ul><ul><ul><li>erythematous maculopapules </li></ul></ul></ul></ul><ul><ul><ul><ul><li>diffuse, pruritic vesicles </li></ul></ul></ul></ul>
  63. 63. Differential diagnosis <ul><li>varicella reactivated </li></ul><ul><ul><ul><li>few constitutional symptoms </li></ul></ul></ul><ul><ul><ul><li>localized pain and paresthesias 2 to 3 days before the eruption </li></ul></ul></ul><ul><ul><ul><li>grouped vesicles in a dermatomal distribution </li></ul></ul></ul>
  64. 64. Differential diagnosis <ul><li>Impetigo </li></ul><ul><ul><li>all age groups, but is usually seen in young children </li></ul></ul><ul><ul><li>Streptococcus pyogenes or Staphylococcus aureus </li></ul></ul><ul><ul><li>involves the face </li></ul></ul><ul><ul><li>has regional lymphadenopathy </li></ul></ul><ul><ul><li>self-limited to 2 to 3 weeks </li></ul></ul><ul><ul><li>vesicles may progress to pustules  easily rupture  honey - colored crust </li></ul></ul>
  65. 65. Differential diagnosis <ul><li>Impetigo </li></ul>
  66. 66. Differential diagnosis <ul><li>psoriasis </li></ul><ul><ul><li>thick(espeso) silver - scaled plaques </li></ul></ul><ul><ul><li>over bright erythema </li></ul></ul><ul><ul><li>extensor surfaces </li></ul></ul><ul><li>mycosis fungoides (Primary cutaneous T-cell lymphoma) </li></ul><ul><ul><li>asymmetric </li></ul></ul><ul><ul><li>finely scaled(descamadas) plaques on the trunk and groin(ingle) </li></ul></ul>
  67. 67. Differential diagnosis <ul><li>psoriasis </li></ul><ul><ul><li>thick(espeso) silver - scaled plaques </li></ul></ul><ul><ul><li>over bright erythema </li></ul></ul><ul><ul><li>extensor surfaces </li></ul></ul><ul><li>mycosis fungoides (Primary cutaneous T-cell lymphoma) </li></ul><ul><ul><li>asymmetric </li></ul></ul><ul><ul><li>finely scaled(descamadas) plaques on the trunk and groin(ingle) </li></ul></ul>
  68. 68. Differential diagnosis <ul><li>*biopsy </li></ul><ul><ul><li>low utility in ACD </li></ul></ul><ul><ul><ul><li>histologic finding of spongiosis is not specific among eczematous dermatoses </li></ul></ul></ul>
  69. 69. Anatomic approach <ul><li>Exposure to the suspect allergen - congruent - distribution of the eruption </li></ul><ul><li>more exposed areas </li></ul><ul><ul><li>the hands </li></ul></ul><ul><ul><li>face </li></ul></ul><ul><ul><ul><li>> ƒ presenting ACD </li></ul></ul></ul>
  70. 70. Anatomic approach <ul><li>Head and neck </li></ul><ul><li>Scalp have greater resistance than  face, ears, and neck </li></ul><ul><ul><li>Hair dyes(tintes) </li></ul></ul><ul><ul><li>Shampoos </li></ul></ul><ul><ul><ul><li>often spare the scalp but involve its nearby landmarks </li></ul></ul></ul><ul><li>eyelids and cheeks(mejillas) </li></ul><ul><ul><li>facial cosmetics </li></ul></ul><ul><ul><li>products applied to the hands  nail polish(esmalte) </li></ul></ul>
  71. 71. Anatomic approach <ul><li>Head and neck </li></ul><ul><li>common triggers </li></ul><ul><ul><li>Metals from jewelry piercings - face and ears </li></ul></ul><ul><ul><li>Topical antibiotics </li></ul></ul><ul><ul><ul><li>Eyes </li></ul></ul></ul><ul><ul><ul><li>Ears </li></ul></ul></ul>
  72. 72. Anatomic approach <ul><li>Neck </li></ul><ul><ul><li>cosmetics and fragrances </li></ul></ul><ul><ul><li>metals </li></ul></ul><ul><ul><li>exotic woods from necklaces (collares) </li></ul></ul><ul><ul><li>musical instruments </li></ul></ul>
  73. 73. Anatomic approach <ul><li>Extremities </li></ul><ul><li>50% involve the hands </li></ul><ul><ul><li>supposed innocuous items </li></ul></ul><ul><ul><ul><li>foods </li></ul></ul></ul><ul><ul><ul><li>moisturizers </li></ul></ul></ul><ul><ul><ul><li>musical instruments, </li></ul></ul></ul><ul><ul><ul><li>protective gloves </li></ul></ul></ul><ul><ul><ul><ul><li>> ƒ fingertips (pulpejos) </li></ul></ul></ul></ul>
  74. 74. Anatomic approach <ul><li>Extremities </li></ul><ul><ul><li>ƒ dorsal side of the hands </li></ul></ul><ul><ul><ul><li>the skin is thinner </li></ul></ul></ul><ul><ul><ul><li>density of Langerhans cells is greater than on the palmar side </li></ul></ul></ul><ul><ul><li>Bracelets, watches, and rings </li></ul></ul><ul><ul><ul><li>ACD  metal exposure </li></ul></ul></ul><ul><ul><ul><li>ICD  soap and detergent accumulation under </li></ul></ul></ul>
  75. 75. Anatomic approach <ul><li>Extremities </li></ul><ul><ul><ul><li>photosensitive process </li></ul></ul></ul><ul><ul><ul><ul><li>hand dermatitis - contiguous with forearms - associated with a facial dermatitis </li></ul></ul></ul></ul><ul><ul><ul><li>dorsal aspect - feet </li></ul></ul></ul><ul><ul><ul><ul><li>chrome - tanned leather (cuero) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>glues (pegamentos) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>rubber (caucho) </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>components of shoes </li></ul></ul></ul></ul></ul>
  76. 76. Anatomic approach <ul><li>Extremities </li></ul><ul><ul><li>Stasis dermatitis - lower legs - chronic varicose inflammation </li></ul></ul><ul><ul><ul><li>Significantly increases the risk of ACD from topically applied products </li></ul></ul></ul><ul><ul><li>Metals – keys - coins -match boxes(encendedores) - pants pockets upper legs </li></ul></ul>
  77. 77. Anatomic approach <ul><li>Torso and groin(ingle) </li></ul><ul><li>Fragrances - deodorants - axillary vault </li></ul><ul><li>formaldehyde, detergents, and dyes from clothes  torso - axillary folds - sparing vault </li></ul><ul><li>Rubber chemicals - elastic of under garments (prendas femeninas) - bra line – waistline (cintura) </li></ul><ul><li>periumbilical region - metallic fasteners(cierrres) – belts(cinturones) – pants </li></ul>
  78. 78. Anatomic approach <ul><li>Torso and groin(ingle) </li></ul><ul><li>Incontinent  bed – bound(obligados) patients - urine - diaper (pañal) </li></ul><ul><li>ƒ Contraceptive devices  latex-sensitive </li></ul><ul><li>Medicines, douches, spermicides  genital area - vulva and adjacent thighs(muslos) ≠ vaginal mucosa </li></ul>
  79. 79. Anatomic approach <ul><li>Oral mucosa </li></ul><ul><li>Langerhans cells are sparse(escasas) at mucosal sites </li></ul><ul><li>contact stomatitis </li></ul><ul><ul><li>contact gingivitis </li></ul></ul><ul><ul><li>cheilitis </li></ul></ul><ul><ul><ul><li>Dental metals - amalgams </li></ul></ul></ul><ul><ul><ul><ul><li>Nickel </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Palladium </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Mercury </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Gold </li></ul></ul></ul></ul>
  80. 80. Anatomic approach <ul><li>Oral mucosa </li></ul><ul><ul><li>saliva - buffering and diluting effect on the allergen </li></ul></ul><ul><ul><li>rapid dispersal and absorption of the allergen  extensive vascularity in the mouth </li></ul></ul><ul><ul><ul><li>low incidence of contact stomatitis </li></ul></ul></ul>
  81. 81. Anatomic approach <ul><li>Systemic involvement </li></ul><ul><li>Systemic ACD - form of autoeczematization - known as an ‘‘id reaction.’’ </li></ul><ul><li>Secondary dermatitis - patients sensitized topically - subsequently re-exposed systemically </li></ul><ul><ul><li>re-exposure </li></ul></ul><ul><ul><ul><li>orally </li></ul></ul></ul><ul><ul><ul><li>intravenously </li></ul></ul></ul><ul><ul><ul><li>intramuscularly </li></ul></ul></ul><ul><ul><ul><li>rectally </li></ul></ul></ul><ul><ul><ul><li>vaginally </li></ul></ul></ul><ul><ul><ul><li>inhalation </li></ul></ul></ul><ul><ul><ul><li>after dental </li></ul></ul></ul><ul><ul><ul><li>surgical devices implanted </li></ul></ul></ul>
  82. 82. Anatomic approach <ul><li>Systemic involvement  ‘‘id reaction.’’ </li></ul><ul><li>Generalized eruption - result - hematogenous dissemination - antigen-specific Th1 cells </li></ul><ul><li>Common contact allergens </li></ul>
  83. 83. Allergens <ul><li>Poison ivy </li></ul><ul><ul><li>specie: Toxicodendron genus </li></ul></ul><ul><ul><li>plant family: Anacardiaceae </li></ul></ul><ul><ul><li>the most ubiquitous of four especies </li></ul></ul><ul><ul><li>family includes </li></ul></ul><ul><ul><ul><li>poison sumac </li></ul></ul></ul><ul><ul><ul><li>poison oak </li></ul></ul></ul>
  84. 84. Allergens <ul><li>Poison ivy </li></ul><ul><ul><li>United States - responsible -more cases – ACD </li></ul></ul><ul><ul><li>Strong sensitizing allergen  urushiol - catechol derivative – sap (savia) </li></ul></ul><ul><ul><ul><li>sap - difficult to wash off </li></ul></ul></ul><ul><ul><ul><li>washing - ideally within 10 minutes of exposure </li></ul></ul></ul><ul><ul><li>dermatitis </li></ul></ul><ul><ul><ul><li>linear erythema and vesicles </li></ul></ul></ul><ul><ul><ul><li>vesicular fluid - no allergenic </li></ul></ul></ul>
  85. 85. Allergens <ul><li>Poison ivy </li></ul><ul><ul><li>chronicity and spread(propagación) of symptoms </li></ul></ul><ul><ul><ul><li>continued unintentional exposure </li></ul></ul></ul><ul><ul><ul><li>urushiol may persist on clothing, tools, sports equipment, - fur(piel) of pets(animals) </li></ul></ul></ul><ul><ul><li>Cross-reactions - catechol derivatives- found in other members - Anacardiaceae family </li></ul></ul><ul><ul><ul><li>Mangoes </li></ul></ul></ul><ul><ul><ul><li>Cashews </li></ul></ul></ul><ul><ul><ul><li>Ginkgoes </li></ul></ul></ul><ul><ul><ul><li>Brazilian peppers(pimienta) </li></ul></ul></ul>
  86. 86. Allergens <ul><li>Metals </li></ul><ul><li>Nickel </li></ul><ul><ul><li>most common metal allergen </li></ul></ul><ul><ul><li>prevalence women higher - early sensitization  ear piercings </li></ul></ul><ul><li>Other </li></ul><ul><ul><ul><ul><li>Chromium </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cobalt </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Gold </li></ul></ul></ul></ul><ul><ul><ul><ul><li>organic forms of mercury </li></ul></ul></ul></ul>
  87. 87. Allergens <ul><li>Metals </li></ul><ul><li>Sensitivity to aluminum is quite uncommon </li></ul><ul><ul><li>substitution with aluminum items - workplace - reduce the incidence </li></ul></ul><ul><li>metal alloys(aleación) - medical devices – implants </li></ul><ul><ul><ul><li>stainless steel  contains - nickel and chromium </li></ul></ul></ul><ul><ul><ul><ul><li>may present - persistent - localized or generalized eczema - loosening - implant </li></ul></ul></ul></ul><ul><ul><ul><li>Patch testing - metals - low specificity - moderate sensitivity  work-up - metal implant </li></ul></ul></ul>
  88. 88. Allergens <ul><li>Medications </li></ul><ul><li>Topical antibiotics </li></ul><ul><ul><li>> ƒ neomycin and bacitracin </li></ul></ul><ul><ul><li>*mupirocin may to be a safe alternative </li></ul></ul><ul><li>Topical anesthetics </li></ul><ul><ul><li>ester class </li></ul></ul><ul><ul><ul><li>benzocaine and tetracaine  ƒ </li></ul></ul></ul><ul><ul><ul><ul><li>lidocaine, dibucaine, and mepivacaine, are rare sensitizers </li></ul></ul></ul></ul>
  89. 89. Allergens <ul><li>Medications </li></ul><ul><li>Topical corticosteroids </li></ul><ul><ul><li>structure may be altered to induce allergenicity </li></ul></ul><ul><ul><ul><li>metabolism in the skin </li></ul></ul></ul><ul><ul><ul><li>degradative reactions within the pharmaceutical preparation </li></ul></ul></ul><ul><li>topical antihistamines </li></ul><ul><ul><li>known to act as sensitizers </li></ul></ul><ul><ul><li>may predispose to an id reaction after systemic administration </li></ul></ul>
  90. 90. Allergens <ul><li>Medications </li></ul><ul><li>Ethylenediamine </li></ul><ul><ul><li>Common allergenic preservative </li></ul></ul><ul><ul><li>found in </li></ul></ul><ul><ul><ul><li>aminophylline </li></ul></ul></ul><ul><ul><ul><li>some antihistamines </li></ul></ul></ul><ul><ul><ul><li>sometopical medicines </li></ul></ul></ul>
  91. 91. Allergens <ul><li>Medications </li></ul><ul><li>thimerosal </li></ul><ul><ul><li>Preservative with the highest prevalence of positive patch tests </li></ul></ul><ul><ul><li>found in </li></ul></ul><ul><ul><ul><li>vaccines </li></ul></ul></ul><ul><ul><ul><li>numerous topical medicines for the eyes, ears, and nose </li></ul></ul></ul>
  92. 92. Allergens <ul><li>Latex and rubber(caucho) chemicals </li></ul><ul><li>Latex fluid - Brazilian rubber tree - Hevea brasiliensis </li></ul><ul><li>Vulcanization </li></ul><ul><ul><li>Chemical accelerators </li></ul></ul><ul><ul><li>Antioxidants </li></ul></ul><ul><ul><ul><li>Thiurams </li></ul></ul></ul><ul><ul><ul><li>Carbamates </li></ul></ul></ul><ul><ul><ul><li>Mercaptobenzothiazole </li></ul></ul></ul><ul><ul><ul><ul><li>*primary sensitizers </li></ul></ul></ul></ul>
  93. 93. Allergens <ul><li>Latex and rubber(caucho) chemicals </li></ul><ul><li>Immediate hypersensitivity reactions </li></ul><ul><ul><li>mediated - specific IgE against - latex protein </li></ul></ul><ul><ul><ul><li>Responses </li></ul></ul></ul><ul><ul><ul><ul><li>Urticaria </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Rhinitis </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Conjunctivitis </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Asthma </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Anaphylaxis </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>within minutes </li></ul></ul></ul></ul></ul>
  94. 94. Allergens <ul><li>Latex and rubber(caucho) chemicals </li></ul><ul><li>*airborne(aera) exposure proteins-Latex </li></ul><ul><li>latex gloves – to cause </li></ul><ul><ul><li>immediate-type reactions </li></ul></ul><ul><ul><li>delayed-type reactions – ACD </li></ul></ul><ul><ul><li>> ƒ ICD. </li></ul></ul>
  95. 95. Allergens <ul><li>Formaldehyde </li></ul><ul><li>Formaldehyde itself </li></ul><ul><li>formaldehyde–releasers = quaternium-15, are the most common </li></ul><ul><ul><li>ƒ preservative ≠ thimerosal  ACD </li></ul></ul><ul><ul><ul><li>cosmetics </li></ul></ul></ul><ul><ul><ul><li>moisturizers </li></ul></ul></ul><ul><ul><ul><li>fabrics (telas) </li></ul></ul></ul>
  96. 96. Allergens <ul><li>Fragrances </li></ul><ul><ul><ul><li>Cosmetics </li></ul></ul></ul><ul><ul><ul><li>Fabrics </li></ul></ul></ul><ul><ul><ul><li>topical medicines </li></ul></ul></ul><ul><ul><ul><li>flavorings (aromatizantes) of foods </li></ul></ul></ul><ul><ul><ul><li>drinks </li></ul></ul></ul><ul><ul><ul><li>spices (especias) </li></ul></ul></ul><ul><ul><ul><li>oral hygiene products </li></ul></ul></ul><ul><ul><ul><li>perfumes and colognes </li></ul></ul></ul>
  97. 97. Allergens <ul><li>Fragrances </li></ul><ul><ul><li>Balsam of Peru >ƒ ACD - nonallergic contact urticaria </li></ul></ul><ul><ul><ul><li>*In addition to mentioned products </li></ul></ul></ul><ul><ul><ul><ul><li>Sunscreens </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Shampoos </li></ul></ul></ul></ul><ul><ul><ul><li>beneficial actions - side effects </li></ul></ul></ul><ul><ul><ul><ul><li>stimulate capillary beds  increase local circulation </li></ul></ul></ul></ul>
  98. 98. Patch testing <ul><li>gold standard – Dx ACD </li></ul><ul><li>first use </li></ul><ul><ul><li>1895 </li></ul></ul><ul><ul><li>Josef Jadassohn </li></ul></ul><ul><ul><li>suspected - rash - result - mercury sensitivity </li></ul></ul><ul><li>refined- simple </li></ul><ul><ul><li>reproducing – ACD </li></ul></ul><ul><ul><ul><li>allergen - same or cross-reacting </li></ul></ul></ul><ul><ul><ul><li>small area – back </li></ul></ul></ul>
  99. 99. Patch testing <ul><li>Standardized allergens- delivery vehicles </li></ul><ul><li>ACD eruption  appears - 2 to 3 days of sufficient allergen contact </li></ul><ul><ul><li>patch testing - performed - at least a 3-day period </li></ul></ul><ul><li>number of allergens - depends </li></ul><ul><ul><li>physician’s clinical suspicion </li></ul></ul><ul><ul><li>likely culprits </li></ul></ul>
  100. 100. Patch testing <ul><li>Screening panels - 20 to 30 - most prevalent allergens </li></ul><ul><ul><li>>ƒ TRUE Test (Mekos Laboratories A/S, Hillerød, Denmark) </li></ul></ul><ul><ul><ul><li>23 allergens </li></ul></ul></ul><ul><ul><ul><li>one negative control </li></ul></ul></ul><ul><ul><ul><ul><li>gel delivery system </li></ul></ul></ul></ul><ul><ul><ul><li>Identifies about 70% - clinically relevant allergens </li></ul></ul></ul>
  101. 101. Patch testing <ul><li>*Another option  assortments(diversidad) of allergens </li></ul><ul><li>Filter paper in 8-mm aluminum disks  ‘‘Finn Chambers’’ (Epitest Ltd Oy, Tuusula, Finland) </li></ul><ul><ul><li>allergen dispersion -Along - 5-mm ribbon of petrolatum - </li></ul></ul>
  102. 102. Patch testing <ul><li>Techniques </li></ul><ul><li>Applied Allergens together </li></ul><ul><li>hairless region </li></ul><ul><li>upper back </li></ul><ul><li>between - spine and scapula </li></ul><ul><li>zone washed </li></ul>
  103. 103. Patch testing <ul><li>Techniques </li></ul><ul><li>An adhesive keeps the allergens secured </li></ul><ul><li>Edges(bordes) - marked with a pen. </li></ul><ul><li>Patients - return - physician’s office - 48 to 72 hours </li></ul><ul><ul><li>Removed patch - Waiting 20 to 30 minutes reactions are graded </li></ul></ul><ul><ul><li>Third visit 24 to 96 hours later </li></ul></ul>
  104. 104. Patch testing <ul><li>Techniques </li></ul><ul><li>longer allergic response </li></ul><ul><ul><li>Elderly patients </li></ul></ul><ul><ul><li>allergens - late phase reactions </li></ul></ul><ul><ul><ul><ul><ul><li>cobalt </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>neomycin </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>topical corticosteroids </li></ul></ul></ul></ul></ul>
  105. 105. Patch testing <ul><li>Precautions </li></ul><ul><li>Not be performed in - acute or widespread(extendida) contact dermatitis </li></ul><ul><ul><li>Positive patch test reaction may progress to autoeczematization </li></ul></ul><ul><li>Pruritus within minutes of application </li></ul><ul><ul><li>suspicions - contact urticaria - possibility  anaphylaxis if patch is not removed </li></ul></ul>
  106. 106. Patch testing <ul><li>to consider </li></ul><ul><li>bacitracin and gold are not TRUE Test panels  prevalent allergens </li></ul><ul><li>Poison ivy also is not included  urushiol’s sensitizing  may cause severe reactions </li></ul><ul><li>May need to be delayed - potent topical steroids -near test site </li></ul><ul><li>Systemic steroids </li></ul><ul><ul><li>doses of 20 mg or less of prednisone daily - not inhibit positive reactions </li></ul></ul>
  107. 107. Patch testing <ul><li>to consider </li></ul><ul><li>bacitracin and gold are not TRUE Test panels  prevalent allergens </li></ul><ul><li>Poison ivy also is not included  urushiol’s sensitizing  may cause severe reactions </li></ul><ul><li>May need to be delayed - potent topical steroids -near test site </li></ul><ul><li>Systemic steroids </li></ul><ul><ul><li>doses of 20 mg or less of prednisone daily - not inhibit positive reactions </li></ul></ul>
  108. 108. MANAGEMENT <ul><li>treating the active case </li></ul><ul><li>Prevention </li></ul><ul><li>treatment </li></ul><ul><ul><li>Topical corticosteroids </li></ul></ul><ul><ul><li>Soap substitutes </li></ul></ul><ul><ul><li>Emollients </li></ul></ul><ul><li>Second line treatments </li></ul><ul><ul><li>topical PUVA </li></ul></ul><ul><ul><li>azathioprine </li></ul></ul><ul><ul><li>cyclosporin </li></ul></ul><ul><ul><ul><li>steroid resistant chronic dermatitis </li></ul></ul></ul>
  109. 109. MANAGEMENT
  110. 110. MANAGEMENT
  111. 111. MANAGEMENT
  112. 112. MANAGEMENT <ul><li>PREVENTION </li></ul><ul><li>workplace  eliminating harmful exposures </li></ul><ul><ul><li>substitution of chemicals  less irritating or allergenic </li></ul></ul><ul><ul><li>introduction of engineering controls </li></ul></ul><ul><ul><li>Organization of work  all employees are exposed to the same degree </li></ul></ul><ul><ul><li>Uses of personal protection </li></ul></ul><ul><ul><ul><li>Gloves </li></ul></ul></ul><ul><ul><li>Selection of less susceptible individuals </li></ul></ul>
  113. 113. MANAGEMENT <ul><li>correct selection of gloves </li></ul><ul><ul><li>Cotton gloves </li></ul></ul><ul><ul><ul><li>allow the skin to ‘‘breathe’’ </li></ul></ul></ul><ul><ul><ul><li>could be used for dry work </li></ul></ul></ul><ul><ul><ul><li>Wet work  thin cotton gloves </li></ul></ul></ul><ul><ul><ul><ul><li>absorb sweat </li></ul></ul></ul></ul><ul><ul><ul><ul><li>inside rubber or vinyl gloves </li></ul></ul></ul></ul>
  114. 114. MANAGEMENT <ul><li>Barrier creams </li></ul><ul><ul><li>questionable value in protecting against contact with irritants </li></ul></ul><ul><li>After-work creams </li></ul><ul><ul><li>Controlled clinical trials have shown benefit  reducing the incidence and prevalence </li></ul></ul><ul><ul><li>approved industrial skin cleansers </li></ul></ul>
  115. 115. MANAGEMENT <ul><li>PRE-EMPLOYMENT SCREENING </li></ul><ul><ul><li>predisposing factors </li></ul></ul><ul><ul><ul><li>Atopic dermatitis </li></ul></ul></ul><ul><ul><ul><li>hand eczema </li></ul></ul></ul><ul><ul><ul><li>xerosis </li></ul></ul></ul>
  116. 116. MANAGEMENT <ul><li>WORK RELATED EDUCATIONAL PROGRAMMES </li></ul><ul><ul><li>Half  OCDs  appear  first two years of employment </li></ul></ul><ul><ul><li>recognition of early signs and symptoms </li></ul></ul><ul><ul><li>proper use of protective clothing </li></ul></ul><ul><ul><li>after-work creams </li></ul></ul><ul><ul><li>personal and environmental hygiene </li></ul></ul>
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