Acd by aseem
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Acd by aseem

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Acd by aseem Acd by aseem Presentation Transcript

  • ALLERGIC CONTACT DERMATITIS (ACD)
  • INTRODUCTION • Von Pirquet (1906) - Gk: ‘Allos’ = Other ; ‘Ergon’ – Work • 1840 - Dakin  Dermatitis Venenata / Rhus dermatitis • Bloch / Steiner-Worlich  Allergic Sensitization of skin (Primula sp) • Haxthausen (1942)  ‘Allergy stems from within’ • Landsteiner / Chase (1949)  hypersensitivity reaction to HAPTENS Cell-mediated • Staedler (1847) – Blotting paper patch test ; modified by Jadassohn – Dermatitis Medicamentosa
  • DEFINITION • type of contact dermatitis • Delayed cell-mediated HSN • manifestation of an allergic response • contact with an exogenous substance • previous sensitization
  • EPIDEMIOLOGY • 3700 documented allergens • Children > Adults • Females > Males ? Ni ? Fragnance Mix • Males : 10-19 % Occupational (44% - Hand Dermatitis)
  • ETIOPATHOGENESIS • Type IV HSN • T-cell mediated Inflammation to Haptens • Genetic Susceptibility  HLA alleles to Co / Ni / Cr • Sensitization (Induction) – Elicitation – Resolution • Hapten + Epidermal Carrier Protein (LC) = Contact Allergen • Contact Allergen conjugate recognized by LC  Presented to T-cells • Internalized to LNs  LCs differentiate into DCs
  • PATHOGENESIS • AA
  • CLINICAL FEATURES • A
  • • ACUTE : pruritic papules and vesicles on an erythematous base Erosions , crusting • Edema in areas of higher absorption coefficient – Mucosae / Eyelids / Genitals • CHRONIC : Lichenified pruritic plaques , scaling • Initial Site localization – causal
  • REGIONAL DISTRIBUTION
  • ACUTE ACD 10
  • ACUTE ACD 11
  • CHR ACD 12
  • VARIANTS • Mucosae - Contact Aphthae / Lingual erosions / Peri-anal dermatitis ; more in Geriatric group  Poor hygeine , incontinence , mucosal dryness • PARADOXICAL ACD Weak allergens Contact / Damaged Epidermis Gold on Metal Oxides Paraben / Lanolin Eczema Topical Corticosteroids
  • • Eythroderma / Exfoliative Dermatitis • EM – Ni / Poison Ivy / Hair dye / Neomycin • Non-Eczematous : Contact Purpura / Contact Leucoderma / Lichenoid AC Reactions / Erythema Dyschromia Perstans • Allergic Contact Urticaria (ACU) – IgE ; Latex Rubber / Colophony / Bacitracin
  • • Systemic Eczematization (Immunological Memory + Secondary Systemic Exposure) • ACD SYNDROME
  • DDx • aa
  • DDx • a
  • DIAGNOSIS • DETAILED HISTORY • CLINICAL EXAM / REGIONAL ALGORITHM • PATCH TESTING +/- ROAT • SPOT TESTS (DIMETHYLGLOXAMINE TEST) • HISTOPATHOLOGY
  • PATCH TESTING (IN-VIVO) • ISS (Indian Standard Series) • TRUE (Thin-layer Rapid Use ; Epicutaneous) • Other Series (Plant / Food / Vegetable / Fragnance / Cosmetic / Textile) ‘Gold Standard’
  • INTERPRETATION • − (0) Negative reaction • ?+ Doubtful reaction; erythema only • + (1+) Weak (nonvesicular) positive allergic reaction; erythema, infiltration and possibly papules • ++ (2+) Strong (vesicular) positive allergic reaction; erythema, infiltration, papules and vesicles • +++ (3+) Extreme positive allergic reaction; bullous reaction • IR Irritant reaction
  • PATCH TESTING (IN-VITRO) • LEUKOCYTE TRANSFORMATION INHIBITION • MACROPHAGE MIGRATION INHIBITION • LYMPH NODE ASSAY
  • HPE • Spongiosis • Eosinophillic Folliculitis • Microvesicle formation • Perivascular infiltrate in Dermis ; granuloma formation noted
  • MANAGEMENT • PHARMACOTHERAPY – Aluminium Sulfate / Calcium Acetate – Emollients – Topical Antipruritic agents – Antihistaminics – Corticosteroids (topical / Oral) – Calcineurin Inhibitors (topical / Oral)
  • PHOTOTHERAPY P-UVA NBUVB PREVENTION ?? HYPOSENSITIZATION / TOLERANCE INDUCTION
  • THANK YOU