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Back to the Basics LMCC Preparation Dermatology. Jim Walker Assoc. Clinical Prof. Medicine Dermatology. Websites. Ottawa U Dermatology Block Slides http://www.med.uottawa.ca/curriculum/dermato.htm UBC Dermatology Undergraduate Problem Based Learning Modules http://www.derm.ubc.ca/teaching
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Back to the BasicsLMCC PreparationDermatology Jim Walker Assoc. Clinical Prof. Medicine Dermatology
Websites • Ottawa U Dermatology Block Slideshttp://www.med.uottawa.ca/curriculum/dermato.htm • UBC Dermatology Undergraduate Problem Based Learning Moduleshttp://www.derm.ubc.ca/teaching • Good Quiz site & Resource – Johns Hopkins Univ.http://dermatlas.med.jhmi.edu/derm/ • eMedicine Textbookhttp://www.emedicine.com/derm/index.shtml • Medlinehttp://www.ncbi.nlm.nih.gov/pubmed • University of Iowa Dept of Dermatologyhttp://tray.dermatololgy/uiowa.edu/home.html • Dermatology Online Atlashttp://dermis.multimedica.de/ • * Please do not use images without attribution or permission!
Morphology • Living gross pathology of skin, hair nails and visible mucosae • Review basic lesions, the nouns (papules, ulcers etc.) • Add the adjectives (size, shape, colour, texture, etc.) • Consider distribution, symmetry and pattern • Visual literacy: simple descriptions→complex interpretations (you see, but do you observe?) • Excellent lighting • Position patient • Look all over (skin, mucosa, hair, nails) • Observe and think
Dermatopathology Pathology – high degree of clinical pathological correlation Assess depth of lesion in skin
Bacterial Skin Disease • Barrier – dry, tough, acidic, Ig in sweat, epidermal turnover every 28 days • Normal Flora: Gm+, yeasts, anaerobes, Gm-
Bacterial Skin Diseases • Impetigo • Bullous and non-bullous • Folliculitis/furuncle • Erysipelas/cellulitis • Necrotizing Fasciitis • Toxin diseases: SSSS, Scarlet fever, toxic shocks • Superantigen: Staph. aureus in atopic derm. • Pseudomonas: warm, moist, alkaline
Impetigenized Atopic (Non-bullous) Staph. > strep.
Erysipelas -Strep. pyogenes -Dermal infection -Asymmetrical, sharp demarcation -Spreading -Septic patient Treatment Oral – amoxacillin 500 QID x 14 days IV – if severe or recurrent, or co-morbidities
Cellulitis – haemorrhagic -usually Strep. pyogenes -deep dermal and sub- cutaneous Treat – as for erysipelas, but cover for Staph.
Necrotizing Fasciitis -Pain out of proportion to apparent lesion -Strep or multi-bacterial deep infection -Emergency debridement and multiple IV antibiotics
Meningococcal septicaemia Petechiae Purpura Necrosis Treatment -blood cultures -immediate IV antibiotics -lumbar puncture -support for gram negative endotoxic shock
Meningococcal Disease • Septicemia vs meningitis - 40-70% vs 10% mortality • Peaks: infancy to 5 years - Second peak age 15 • Infection and Endotoxin and DIC cause damage • Rash subtle at first - Erythema→purpura →necrosis - Search for petechiae / purpura - “any febrile child with a petechial rash should be considered to have meningococcal septicemia, and treatment should be commenced without waiting for further confirmation.”
SSSS primary Staph. infection conjunctivitis
Staph. Scalded Skin Syndrome SSSS – same child, back, sterile blisters -epidermolytic toxin mediated disease
31 yr. gay male admitted for biopsy of lymph node for expected lymphoma. Rash noted, dermatology consulted.Widespread papular eruption with adenopathy.
Soles of same patient. Your diagnosis?
Secondary syphilis -a systemic disease -order STS and treponemal tests -LP? Treatment -Benzathine penicillin 2.4 million units IM -Herxheimer reaction -follow STS -report disease -contact tracing -check for other venereal diseases
Secondary syphilis Condylomata lata
Viral Skin Disease • DNA – tend to proliferate on skin • RNA – tend to be erythemas/exanthems • Exanthem – epidermal/skin • Enanthem - mucosal
Definitions • Exanthem(s) = Exanthema(ta), (Greek) • A bursting out (ex) in flowers (anthema) • Any dermatosis that erupts or “flowers” quickly • Only the erythemas are numbered • Includes papular, vesicular, pustular eruptions
Classic ExanthemsErythemas of Childhood 1 Rubeola - Measles 2 Scarlet Fever 3 Rubella – German Measles 4 Kawasaki disease 5 Erythema Infectiosum 6 Roseola Infantum - Exanthem Subitum
Human Herpes Virus 1 HSV-1 2 HSV-2 3 VZV 4 EBV 5 CMV 6 Roseola 7 ? 8 Kaposi’s Sarcoma
Measles – morbilliform erythema Red measles = rubeola Koplick’s spots in oral mucosa, early
Rubella with post auricular nodes (German measles)
Erythema infectiosum = Parvo virus B19 = slapped cheek syndrome
Erythema infectiosum Reticulate erythema on arms Treatment – supportive Systemic -arthritis in adults -hydrops fetalis -anaemia
Toxic erythema • -viral • -scarlet fever • drug • acute collagen vascular disease
Herpes simplex, recurrent, post pneumococcal pneumonia
Eczema herpeticum HSV in atopic dermatitis
Herpes virus, treatment • Acyclovir, famciclovir, valacyclovir • Must treat early (72 hours) • Front end load dose • Shortens course and reduces severity • Does not eliminate virus
Herald plaque - pityriasis rosea annular, NOT fungus Cause unclear, probably infectious (HHV7)
Pityriasis rosea Diagnosis -symmetrical discrete oval salmon-coloured papules and plaques, collarette scales Treatment -UVL -erythromycin 250 QID, early -hydrocortisone cream if itchy -lasts 6-12 weeks, no scars
Plantar Wart -demarcation -dermatoglyphics -micro-haemorrhage -lateral tenderness
(Plantar) Wart, Treatment Summary • Respect natural history • First do no harm • Cryotherapy • Caustics: salicylic acid, lactic acid, cantharadine • Other chemicals: imiquimod, fluorouracil • Immunotherapy: DPCP • Surgery: curette only, no desiccation, no excision • No radiation
HIV – primary exanthem This rash not a problem. It’s the permissive effect of immune suppression that allows other infections and tumors to kill
Primary HIV Infection • Lapins et al BJD 1996, 22 consecutive men • HIV Exposure • Acute illness 11–28 days, Seroconvert in 2–3wks • Fever 22, pharyngitis21, adenopathy21, • Exanthem day 1-5 of illness • Upper trunk and neck, discrete non-confluent red macules and maculopapules in 17 / 22 • Enanthem of palatal erosions in 8 / 22
Fungal Skin Infections • Superficial and Deep • Superficial • Tinea plus location • Tinea = dermatophyte • Lives on keratin (non-viable) • Tinea versicolour is misnomer = dimorphic yeast • Hair and nail infections must be treated systemically (terbinafine, griseofulvin)