Diseases of skin.... more


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Diseases of skin.... more

  2. 2. Learning Objectives <ul><li>Describe the macroscopic and microscopic changes in frequent lesions of the skin. </li></ul><ul><li>Define the most frequent forms of infectious skin disease and their pathogenic organisms. </li></ul>www.freelivedoctor.com
  3. 3. REMEMBERING FEATURES OF NORMAL SKIN www.freelivedoctor.com
  4. 4. www.freelivedoctor.com
  5. 5. <ul><li>1. EPIDERMIS </li></ul><ul><ul><li>Is subdivided into 4 layers: </li></ul></ul><ul><ul><ul><li>Horny layer (stratum corneum) </li></ul></ul></ul><ul><ul><ul><li>Granular layer (stratum granulosum) </li></ul></ul></ul><ul><ul><ul><li>Malpighian layer (prickle-cell layer) </li></ul></ul></ul><ul><ul><ul><li>Basal layer </li></ul></ul></ul><ul><ul><li>There is an extra layer found only in palms/soles  lucid layer </li></ul></ul>www.freelivedoctor.com
  6. 6. <ul><li>...(Continues) </li></ul><ul><ul><li>Keratinocytes are cells that mature from the basal layer to stratum corneum and their function is related to form a barrier, to secrete PGs, leukotrienes, Ils and induction of Vitamin D by UV rays. </li></ul></ul><ul><ul><li>Melanocytes (3%) are dendritic cells derived from the neural crest and located into the basal layer, that produce melanin (endogenous screen against UV rays in sunlight). </li></ul></ul><ul><ul><li>Langerhans cells (4%) can recognize and process Ags and communicate to lymphoid cells. </li></ul></ul>www.freelivedoctor.com
  7. 7. <ul><li>A , The skin is composed of an epidermal layer (e) from which specialized adnexa (hair follicles, h; sweat glands, g; and sebaceous glands, s) descend into the underlying dermis (d). B , This projection of the epidermal layer (e) and underlying superficial dermis demonstrates the progressive upward maturation of basal cells (b) into cornified squamous epithelial cells of the stratum corneum (sc). Melanin-containing dendritic melanocytes (m) (and rare Merkel cells containing neurosecretory granules) and midepidermal dendritic Langerhans cells (lc) are also present. The underlying dermis contains small vessels (v), fibroblasts (f), perivascular mast cells (mc), and dendrocytes (dc), potentially important in dermal immunity and repair. </li></ul>www.freelivedoctor.com
  8. 8. <ul><li>...(Continues) </li></ul><ul><ul><li>Merkel cells (<1%) are located also into the basal layer of skin/mucous membranes and function as tactile mechanoreceptor. </li></ul></ul><ul><ul><li>The basal layer is responsible for epidermal-dermal adherence and probably is a macromolecular filter. It is also a major site for Igs localization. </li></ul></ul>www.freelivedoctor.com
  9. 9. <ul><li>2. DERMIS </li></ul><ul><ul><li>Papillary dermis is immediately beneath the epidermis and is formed by collagen fibers. It reacts conjointly with epidermis and superficial capillary-venular bed. </li></ul></ul><ul><ul><li>Reticular dermis contains most of dermal collagen </li></ul></ul><ul><li>3. EPIDERMAL ADNEXA. </li></ul><ul><ul><li>Includes modified keratinized structures (nails, hair) and sebaceous, eccrine and apocrine glands (axilla, ano-genital areas, nipple and areola) </li></ul></ul><ul><li>4. BLOOD VESSELS, NERVES, LYMPHATICS MUSCLES, CELLS (mast cells) </li></ul>www.freelivedoctor.com
  11. 11. SKIN PATHOLOGY MACROSCOPIC TERMS www.freelivedoctor.com
  12. 12. SKIN PATHOLOGY <ul><li>RESPONSES OF THE SKIN TO INJURY </li></ul><ul><ul><li>Clinical lesions – Macroscopic terms </li></ul></ul><ul><ul><ul><li>Macule </li></ul></ul></ul><ul><ul><ul><li>Patch </li></ul></ul></ul><ul><ul><ul><li>Papule </li></ul></ul></ul><ul><ul><ul><li>Nodule </li></ul></ul></ul><ul><ul><ul><li>Plaque </li></ul></ul></ul><ul><ul><ul><li>Vesicle </li></ul></ul></ul><ul><ul><ul><li>Bulla </li></ul></ul></ul><ul><ul><ul><li>Blister </li></ul></ul></ul><ul><ul><ul><li>Pustule </li></ul></ul></ul><ul><ul><ul><li>Wheal </li></ul></ul></ul><ul><ul><ul><li>Scale </li></ul></ul></ul><ul><ul><ul><li>Lichenification </li></ul></ul></ul><ul><ul><ul><li>Excoriation </li></ul></ul></ul><ul><ul><ul><li>Onycholysis </li></ul></ul></ul>www.freelivedoctor.com
  13. 13. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>MACULE </li></ul></ul><ul><ul><ul><li>A circumscribed lesion of up to 5 mm in diameter, characterized by flatness and usually distinguished from surrounding skin by its coloration. </li></ul></ul></ul><ul><ul><li>PATCH </li></ul></ul><ul><ul><ul><li>A circumscribed lesion of more than 5 mm in diameter, characterized by flatness and usually distinguished from surrounding skin by its coloration. </li></ul></ul></ul>www.freelivedoctor.com
  14. 14. Patch www.freelivedoctor.com
  15. 15. Macules and patches www.freelivedoctor.com
  16. 16. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>PAPULE </li></ul></ul><ul><ul><ul><li>Elevated dome-shaped or flat-topped lesion 5 mm or less across. </li></ul></ul></ul><ul><ul><li>PLAQUE </li></ul></ul><ul><ul><ul><li>Elevated flat-topped lesion usually greater than 5 mm across (may be caused by coalescent papules). </li></ul></ul></ul>www.freelivedoctor.com
  17. 17. Plaque www.freelivedoctor.com
  18. 18. www.freelivedoctor.com
  19. 19. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>NODULE </li></ul></ul><ul><ul><ul><li>Elevated lesion with spherical contour greater than 5 mm across. </li></ul></ul></ul>www.freelivedoctor.com
  20. 20. www.freelivedoctor.com
  21. 21. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>VESICLE </li></ul></ul><ul><ul><ul><li>Fluid-filled raised lesion 5 mm or less across. </li></ul></ul></ul>www.freelivedoctor.com
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  23. 23. www.freelivedoctor.com
  24. 24. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>BULLA </li></ul></ul><ul><ul><ul><li>Fluid-filled lesion greater than 5 mm across. </li></ul></ul></ul>www.freelivedoctor.com
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  26. 26. www.freelivedoctor.com
  27. 27. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>BLISTER </li></ul></ul><ul><ul><ul><li>Common term used for vesicle or bulla. </li></ul></ul></ul>www.freelivedoctor.com
  28. 28. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>PUSTULE </li></ul></ul><ul><ul><ul><li>Discrete, pus-filled, raised lesion. </li></ul></ul></ul>www.freelivedoctor.com
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  31. 31. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>WHEAL </li></ul></ul><ul><ul><ul><li>Itchy, transient, elevated lesion with variable blanching and erythema formed as the result of dermal edema. </li></ul></ul></ul>www.freelivedoctor.com
  32. 32. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>SCAR </li></ul></ul><ul><ul><ul><li>Is a hard plaque of dense fibrotic tissue covered by a thin epidermis. A mark of injury from any sort of process. </li></ul></ul></ul><ul><ul><li>ATROPHY </li></ul></ul><ul><ul><ul><li>Usually refers to thinning of the epidermis  easily wrinkled and/or shiny surface. It may also apply to dermal and/or subcutaneous tissue, with or without changes in epidermis. </li></ul></ul></ul>www.freelivedoctor.com
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  34. 34. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>ULCER </li></ul></ul><ul><ul><ul><li>Loss of skin tissue or substance from the surface downward, leaving an uncovered or denuded wound that is slow to heal. </li></ul></ul></ul><ul><ul><li>EROSION </li></ul></ul><ul><ul><ul><li>A superficial denudation of the skin, usually implying loss of epidermis. </li></ul></ul></ul>www.freelivedoctor.com
  35. 35. www.freelivedoctor.com
  36. 36. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>FISSURE </li></ul></ul><ul><ul><ul><li>Is a vertical splitting/separation of the skin </li></ul></ul></ul><ul><ul><li>CRUST </li></ul></ul><ul><ul><ul><li>Dried surface of fluid, often serous (inspissated serum) in nature, with or without tissue debris (same as “scab”) </li></ul></ul></ul><ul><ul><li>EXCORIATION </li></ul></ul><ul><ul><ul><li>A scratch mark, often with denudation of the skin to form a small ulcer </li></ul></ul></ul>www.freelivedoctor.com
  37. 37. SKIN PATHOLOGY <ul><li>MACROSCOPIC TERMS </li></ul><ul><ul><li>SCALE </li></ul></ul><ul><ul><ul><li>A thin flake of epithelium (mostly of corneum layer) which is separated from the underlying intact skin. </li></ul></ul></ul><ul><ul><li>LICHENIFICATION </li></ul></ul><ul><ul><ul><li>A thickening of the skin and an increase of skin markings, usually seen w/chronic coalescence of papular lesions (atopic eczema). </li></ul></ul></ul><ul><ul><li>ONYCHOLYSIS </li></ul></ul><ul><ul><ul><li>Separation of nail plate from nail bed. </li></ul></ul></ul>www.freelivedoctor.com
  38. 38. SKIN PATHOLOGY MICROSCOPIC TERMS www.freelivedoctor.com
  39. 39. SKIN PATHOLOGY <ul><li>RESPONSES OF THE SKIN TO INJURY </li></ul><ul><ul><li>MICROSCOPIC TERMS </li></ul></ul><ul><ul><ul><li>Hyperkeratosis </li></ul></ul></ul><ul><ul><ul><li>Parakeratosis </li></ul></ul></ul><ul><ul><ul><li>Hypergranulosis </li></ul></ul></ul><ul><ul><ul><li>Acanthosis </li></ul></ul></ul><ul><ul><ul><li>Papillomatosis </li></ul></ul></ul><ul><ul><ul><li>Dyskeratosis </li></ul></ul></ul><ul><ul><ul><li>Acantholysis </li></ul></ul></ul><ul><ul><ul><li>Spongiosis </li></ul></ul></ul><ul><ul><ul><li>Hydropic swelling (ballooning) </li></ul></ul></ul><ul><ul><ul><li>Exocytosis </li></ul></ul></ul><ul><ul><ul><li>Erosion </li></ul></ul></ul><ul><ul><ul><li>Ulceration </li></ul></ul></ul><ul><ul><ul><li>Vacuolization </li></ul></ul></ul><ul><ul><ul><li>Lentiginous </li></ul></ul></ul>www.freelivedoctor.com
  40. 40. SKIN PATHOLOGY <ul><li>MICROSCOPIC TERMS </li></ul><ul><ul><li>HYPERKERATOSIS: </li></ul></ul><ul><ul><ul><li>Thickening of the stratum corneum, often associated with a qualitiative abnormality of the keratin. </li></ul></ul></ul><ul><ul><li>PARAKERATOSIS: </li></ul></ul><ul><ul><ul><li>Modes of keratinization characterized by the retention of the nuclei in the stratum corneum. On mucous membranes, parakeratosis is normal. </li></ul></ul></ul>www.freelivedoctor.com
  41. 41. Hyperkeratosis www.freelivedoctor.com
  42. 42. Parakeratosis www.freelivedoctor.com
  43. 43. SKIN PATHOLOGY <ul><li>MICROSCOPIC TERMS </li></ul><ul><ul><li>HYPERGRANULOSIS: </li></ul></ul><ul><ul><ul><li>Hyperplasia of the statum granulosum, often due to intense rubbing </li></ul></ul></ul><ul><ul><li>ACANTHOSIS: </li></ul></ul><ul><ul><ul><li>Diffuse epidermal hyperplasia </li></ul></ul></ul><ul><ul><li>PAPILLOMATOSIS: </li></ul></ul><ul><ul><ul><li>Surface elevation caused by hyperplasia and enlargement of contiguous dermal papillae. </li></ul></ul></ul>www.freelivedoctor.com
  44. 44. Acanthosis www.freelivedoctor.com
  45. 45. SKIN PATHOLOGY <ul><li>MICROSCOPIC TERMS </li></ul><ul><ul><li>DYSKERATOSIS: </li></ul></ul><ul><ul><ul><li>Abnormal keratinization occurring prematurely within individual cells or groups of cells below the stratum granulosum. </li></ul></ul></ul><ul><ul><li>ACANTHOLYSIS: </li></ul></ul><ul><ul><ul><li>Loss of intercellular connections resulting in loss of cohesion between keratinocytes. </li></ul></ul></ul><ul><ul><li>SPONGIOSIS: </li></ul></ul><ul><ul><ul><li>Intercellular edema of the epidermis. </li></ul></ul></ul>www.freelivedoctor.com
  46. 46. Acantholysis www.freelivedoctor.com
  47. 47. Spongiosis www.freelivedoctor.com
  48. 48. SKIN PATHOLOGY <ul><li>MICROSCOPIC TERMS </li></ul><ul><ul><li>HYDROPIC SWELLING (BALLOONING) </li></ul></ul><ul><ul><ul><li>Intracellular edema of keratinocytes, often seen in viral infections. </li></ul></ul></ul><ul><ul><li>EXOCYTOSIS: </li></ul></ul><ul><ul><ul><li>Infiltration of the epidermis by inflammatory or circulating blood cells. </li></ul></ul></ul>www.freelivedoctor.com
  49. 49. Hydropic swelling (ballooning) www.freelivedoctor.com
  50. 50. SKIN PATHOLOGY <ul><li>MICROSCOPIC TERMS </li></ul><ul><ul><li>VACUOLIZATION: </li></ul></ul><ul><ul><ul><li>Formation of vacuoles within or adjacent to cells; often refers to basal cell-basement membrane zone area. </li></ul></ul></ul><ul><ul><li>LENTIGINOUS: </li></ul></ul><ul><ul><ul><li>Referring to a linear pattern of melanocyte proliferation within the epidermal basal cell layer. Lentiginous melanocytic hyperplasia can occur as a reactive change or as part of a neoplasm of melanocytes. </li></ul></ul></ul>www.freelivedoctor.com
  51. 51. BONUS MATERIAL www.freelivedoctor.com
  52. 52. SKIN PATHOLOGY Bonus Material <ul><li>SKIN RESPONSE IN SYSTEMIC DISEASES. </li></ul><ul><ul><li>HYPERPIGMENTATION -Addison´s disease -Hemochromatosis -Heavy metal poisoning (As,Ag) -Chronic renal failure -Chronic liver disease </li></ul></ul>www.freelivedoctor.com
  53. 53. www.freelivedoctor.com
  54. 54. www.freelivedoctor.com
  55. 55. SKIN PATHOLOGY Bonus Material <ul><li>SKIN RESPONSE IN SYSTEMIC DISEASES </li></ul><ul><li>HYPOPIGMENTATION -Albinism -Chediak-Higashi syndrome -Hypopituitarism </li></ul>www.freelivedoctor.com
  56. 56. www.freelivedoctor.com
  57. 57. SKIN PATHOLOGY – Bonus Material <ul><li>SKIN RESPONSE IN SYSTEMIC... </li></ul><ul><li>DARK SPOTS -Peutz-Jegher´s syndrome -Albright´s syndrome -Neurofibromatosis </li></ul><ul><li>ORANGE-YELLOW PIGMENT -Jaundice -Hypervitaminosis A, etc. </li></ul><ul><li>PRURITUS -Chronic renal failure -Obstructive jaundice -Hodgkin’s disease </li></ul>www.freelivedoctor.com
  58. 58. www.freelivedoctor.com
  59. 59. www.freelivedoctor.com
  60. 60. SKIN PATHOLOGY Bonus Material <ul><li>SKIN RESPONSE IN SYSTEMIC... </li></ul><ul><li>HEMORRHAGIC PETECHIAE -Bacterial endocarditis -Scurvy -Thrombocytopenic purpura -Septicemia -Vasculitis </li></ul><ul><li>BRUISES -Amyloidosis -Leukemia -Bacteremia -Scurvy -Cushing´s syndrome </li></ul>www.freelivedoctor.com
  61. 61. www.freelivedoctor.com
  62. 62. SKIN PATHOLOGY Bonus Material <ul><li>SKIN RESPONSE IN SYSTEMIC... </li></ul><ul><li>TELANGIECTASIA -Chronic liver failure -Osler-Weber-Rendu syndrome </li></ul><ul><li>HIRSUTISM -Cushing’s syndrome -Increased levels of androgens </li></ul><ul><li>HAIR LOSS </li></ul><ul><li>-Hypothyroidism -SLE </li></ul>www.freelivedoctor.com
  63. 63. SKIN PATHOLOGY Bonus Material <ul><li>SKIN RESPONSE IN SYSTEMIC... </li></ul><ul><li>HYPERKERATOSIS -Hypervitaminosis A -Scurvy </li></ul><ul><li>ACANTHOSIS NIGRICANS -Mostly abdominal carcinomas (stomach) -Also: some lung and breast carcinomas </li></ul><ul><li>DERMATITIS -Hypervitaminosis A -Parkinson’s diease -Pellagra </li></ul>www.freelivedoctor.com
  64. 64. www.freelivedoctor.com
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  66. 66. END OF BONUS MATERIAL www.freelivedoctor.com
  68. 68. INFECTION AND INFESTATION <ul><li>Verrucae (warts) </li></ul><ul><ul><li>Common lesions of children and adolescents, may be encountered at any age. </li></ul></ul><ul><ul><li>Caused by human papillomaviruses. </li></ul></ul><ul><ul><li>Generally self-limited, regressing spontaneously. </li></ul></ul><ul><ul><ul><li>Verruca vulgaris </li></ul></ul></ul><ul><ul><ul><li>Verruca plana </li></ul></ul></ul><ul><ul><ul><li>Verruca plantaris </li></ul></ul></ul><ul><ul><ul><li>Verruca palmaris </li></ul></ul></ul><ul><ul><ul><li>Condyloma acuminatum (venereal wart) </li></ul></ul></ul>www.freelivedoctor.com
  69. 69. … (Continues) <ul><li>… (Continues) </li></ul><ul><ul><li>Pathogenesis: </li></ul></ul><ul><ul><ul><li>Anogenital warts are caused predominantly by HPV types 6 and 11 (HPV type 16 shows some degree of dysplasia, associated with in situ squamous cell carcinoma of the genitalia). </li></ul></ul></ul><ul><ul><ul><li>HPV types 5 and 8 have been detected also. </li></ul></ul></ul>www.freelivedoctor.com
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  71. 71. … (Continues) <ul><li>Molluscum Contagiosum </li></ul><ul><ul><li>Is a common self-limited viral disease of the skin caused by a poxvirus (largest pathogenic poxvirus in humans). </li></ul></ul><ul><ul><li>Clinically, multiple lesions may occur on the skin and mucous membranes (trunk and anogenital areas). </li></ul></ul>www.freelivedoctor.com
  72. 72. SKIN PATHOLOGY <ul><li>VIRUSES </li></ul><ul><ul><li>Herpes simplex I (oral blisters) and herpes simplex II (genital blisters). </li></ul></ul><ul><ul><li>Varicella (blisters on trunk  periphery) </li></ul></ul>www.freelivedoctor.com
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  74. 74. … (Continues) <ul><li>Impetigo </li></ul><ul><ul><li>Common superficial bacterial infection of the skin. </li></ul></ul><ul><ul><li>Pathogenesis: </li></ul></ul><ul><ul><ul><li>Beta-hemolytic streptococci and Staphylococcus aureus (most of the cases nowadays). </li></ul></ul></ul>www.freelivedoctor.com
  75. 75. … (Continues) <ul><li>Superficial fungal infections </li></ul><ul><ul><li>Caused primarily by dermatophytes. </li></ul></ul><ul><ul><ul><li>Tinea capitis </li></ul></ul></ul><ul><ul><ul><li>Tinea barbae </li></ul></ul></ul><ul><ul><ul><li>Tinea corporis </li></ul></ul></ul><ul><ul><ul><li>Tinea cruris </li></ul></ul></ul><ul><ul><ul><li>Tinea pedis (athlete’s foot) </li></ul></ul></ul><ul><ul><li>Spread to or primary infection of the nails is referred to as onychomycosis . </li></ul></ul>www.freelivedoctor.com
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  78. 78. … (Continues) <ul><li>… (Continues) </li></ul><ul><ul><li>Tinea versicolor ( Malassezia furfur ), a yeast. </li></ul></ul>www.freelivedoctor.com
  79. 79. … (Continues) <ul><li>Arthropod bites, stings, and infestations </li></ul><ul><ul><li>Arachnida (spiders, scorpions, ticks, and mites) </li></ul></ul><ul><ul><li>Insecta (lice, bedbugs, bees, wasps, fleas, flies, and mosquitoes) </li></ul></ul><ul><ul><li>Chilopoda (centipedes). </li></ul></ul>www.freelivedoctor.com
  80. 80. … (Continues) <ul><li>… (Continues) </li></ul><ul><ul><li>Arthropods can produce lesions: </li></ul></ul><ul><ul><ul><li>1. By direct irritant effects of insesct parts or secretions. </li></ul></ul></ul><ul><ul><ul><li>2. By immediate or delayed hypersensitivity responses (including an anaphylactic reaction) </li></ul></ul></ul><ul><ul><ul><li>3. By specific effects of venoms (e.g. black widow spider venom produces severe cramps and excruciating pain, the brown recluse spider venom contains potent enzymes that produce tissue necrosis) </li></ul></ul></ul><ul><ul><ul><li>4. By serving as vectors for secondary invaders, such as viruses, bacteria, rickettsiae, and parasites. </li></ul></ul></ul>www.freelivedoctor.com
  81. 81. … (Continues) <ul><li>… (Continues) </li></ul><ul><ul><li>Ixodes dammini , a tick vector for the spirochete that causes Lyme disease. </li></ul></ul><ul><ul><li>Pediculosis , caused by the head louse, crab louse, and body louse. </li></ul></ul><ul><ul><li>Scabies , caused by the mite Sarcoptes scabei . </li></ul></ul>www.freelivedoctor.com