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Dermatologic Board Review

Dermatologic Board Review. Lane Bower, MHSc, PA-C. Which is the SK?. Seborreic Keratosis. Most common benign cutaneous neoplasm Origin unknown No malignant potential Easily and quickly removed Vary in size shape, most oval Most common on torso, lesser degree on face

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Dermatologic Board Review

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  1. Dermatologic Board Review Lane Bower, MHSc, PA-C

  2. Which is the SK?

  3. Seborreic Keratosis • Most common benign cutaneous neoplasm • Origin unknown • No malignant potential • Easily and quickly removed • Vary in size shape, most oval • Most common on torso, lesser degree on face • Increasing numbers with age • Leser Tre’lat Sign

  4. Nevus • A benign, pigmented lesion that is not caused by any outside catalyst. • There are many types of nevi; junctional, compound, dermal. Refer to text • Main job is differentiating from dysplastic nevi which have malignant potential

  5. What to do? • When in doubt, remove it and send it to pathology. • Do a conservative full excision • If it just doesn’t look right, remove it • That’s the thing with dysplastic nevi, if you can’t make up your mind as to whether it is benign or a possible melanoma, it is probably the middle ground of dyplastic

  6. Actinic Keratosis • Common, sun induced, pre-malignant, changes that increase with age • Most common sites are forehead, shoulders, back, and dorsum of arms • Start as an erythematous, rough, area, that forms a yellow crust. • They are usually very symmetrical in distribution.

  7. ……actinic keratosis Basal cell and other skin cancers can develop in these transitional type lesions.

  8. Treatment of AK • 5-FU get incorporated in to rapidly reproducing cells and causes cell death • Retin-A has been helpful • Cryotherapy for early lesions is effective • Laser is excellent! • Avoidance of further sun damage is paramount • Explain the Course using 5-FU

  9. Who’s the Mole?

  10. Zosteriform • Lesions arranged along the cutaneous distribution of a spinal dermatome • They are unilateral and denote • herpes zoster • metastatic carcinoma of the breast • dermatomal hemangiomatous growths of Sturge-Weber syndrome

  11. Impetigo • Level of Infection • Epidermal superficial infection • Port of Entry • Cuts, abrasions, bug bite • Likes moist areas (mouth, nose) and hot moist climates • Susceptibility • Common in infants & children • VERY Contagious!

  12. Impetigo • Symptoms • Itch • Signs (Appearance) • Vesicular • Toxins cause epidermal cleavaging of stratum corneum • Some strains Strep. aureus cause thin-roofed bulla • Evolves to pustules and become “honey-crusted” • Satellite lesions on periphery (asymptomatic)

  13. Impetigo • Causative Agents • Staphylococcus aureus (most usual) • ? 2wk incubation • Streptococcus pyrogenes (occ. alone OR together)

  14. Impetigo • Course of Disease • Self-limiting !! • But… • may last weeks or months • Post streptococcal glomerulonephritis may follow! Esp. 2 - 4 yo. Hematuria/proteinuria. • Osteomyelitis, septic arthritis & pneumonia from otherwise seemingly innocuous impetigo

  15. Impetigo • Treatment (cover both Staph & Strep) • All • Wash with anti-bacterial soap 1-2/d to remove crusts. • Wash entire body to prevent spread 1- 2/day

  16. Erysipelas & Cellulitis • Level of Infection • Erysipelas  epidermis & dermis (defined border). • Acute inflammatory version of Cellulitis with streaking. • Cellulitis  dermis & subcutaneous tissue (diffuse) • Symptoms • Area is red, hot, swollen, tender, edema, ?malaise • perhaps vesicles, bullae, petechiae/purpura • Perhaps spread to lymphatics, “red streaks” • lymph nodes may be swollen and tender • chills and fever may be present

  17. Erysipelas & Cellulitis • A portals of entry • Open lesion, trauma, surgical wound, athletes foot, IV drug use, insect bite, fissure • Radiation therapy • Arms usually in young adultsLegs usually in children and older adults • Puerperal sepsis common form before antibiotics • Peripheral vascular disease is a common underlying factor

  18. Erysipelas & Cellulitis • Diagnosis • Largely Clinical: • typical presentation and appearance • Labs • CBC • gram stain and culture wounds poor yield • needle aspiration (5% yield), biopsy (20% yield), blood cultures (5% yield) • Films (?) • Plain / CT / MRI: underlying fasciitis or osteomyelitis • Referrals: (?) Ortho if over joint

  19. Erysipelas & Cellulitis • Differential Diagnosis • Necrotizing Fasciitis: deeper and much more virulent. Consider if patient doesn’t respond to antibiotics within 48 hours. • Deep vein thrombosis • Course • Antibiotics • possible abscess (I&D), sepsis, fasciitis (rare) • Erysipelas  Endocarditis • Recurrent cellulitis  persistent lymphedema

  20. Erysipelas & Cellulitis • Differential Diagnosis • Necrotizing Fasciitis: deeper and much more virulent. Consider if patient doesn’t respond to antibiotics within 48 hours. • Deep vein thrombosis • Course • Antibiotics • possible abscess (I&D), sepsis, fasciitis (rare) • Erysipelas  Endocarditis • Recurrent cellulitis  persistent lymphedema

  21. Erysipelas & Cellulitis • Inpatient • IV methacillinase-resistant penicillin (nafcillin) or cephazolin • Consider pseudomonas in immunocompromised patients--ticarcillin, piperacillin Others: Elevate limbs, treat sources Warning: May get worse first day or two of tx. Draw on pt.

  22. Cellulitis Pitfalls • Necrosis • Devitalized tissue (tense, cyanotic, necrotic, bronzing of the skin, blanched) will not be perfused, so antibiotics will not get to the site. • If not improvement on ABX, consider devitalized tissue & surgical debridement

  23. Cellulitis Pitfalls (cont.) • Facial Cellulitis in adults • H. Flu in adult is rare and may be toxic with airway compromise. (usually >50yo) Admit & tx (cefuroxime IV) • Facial Cellulitis in children • Potentially serious !!!! • If no obvious entry for, probably H. Flu • ? Meningitis (8% infants) ?tap.

  24. Cellulitis Pitfalls (cont.) • Cellulitis around the eye • Dangerous !!! • Orbital vs. Peri-orbital cellulitis • Periorbital (more common) • Limited to eyelids in the preseptal region • Treat aggressively with IV abx • Orbital is EMERGENCY • Infection spreads both by extension and retrograde • H. Flu usual • IV abx, admit, ? CT (globe displacement)

  25. Cellulitis Pitfalls (cont.) • Necrotizing Fasciitis • Dangerous !!! • S. pyrogenes or others • Sx: painful, edema, necrosis, widespread • Occlusion of small blood vessels to gangrene (growth of anaerobes - eg Bacteroides). • Risk factor: DM • Dx: x-rays show gas • Mortality 30% ! Surgical treatment

  26. Upper lid avulsion

  27. Animal Bites • Cats- Pasteurella multocida, S. aureus • Primary Antibiotic Augmentin 875mg BID x 10 days • Alternative- Cefuroxime 500 mg TID x 7dyas • 80% of all cat bites become infected! • DO NOT USE KEFLEX!!!!!!

  28. Animal Bites • Dogs- Pasteurella mutlicoda,S. aureus • Primary- Augmentin 875 mg BID • Alternative- Clindamycin 300 mg QID plus a flouroquinolone ONLY 5% become infected.

  29. Tinea of the Foot • Uncommon in women! • Uncommon in prepubertal children • Inevitable in immunocompromised patients • Acquired from locker-room floors and communal baths • Once infected, patient becomes a carrier and is at risk for recurrence • Tight fitting shoes and work-boots

  30. Tinea Pedis

  31. Treatment • Promote dryness • Drysol 20% (aluminum chloride) H.S. • Topical antifungal (Loprox, Lotrimin, Spectazole) • Sometimes oral if refractory (Lamisil tablets) • Shoes that “breathe” and socks that wick away moisture • Lamb’s wool between the toes • Treat secondary infection!!!!! (staph & pseudomonas)

  32. Special Treatment Considerations • Tinea Capitis is not responsive to topical agents. You must use an oral drug such as Giseofulvin 500 mg. po qd. • Pediatric dosing: 10-20 mg/kg po qd X 4 – 6 weeks. Max 1 g/d. Absorption is better with a fatty meal.

  33. Tinea Cruris • Warm, moist, dark, environment most conducive to growth If any dermatitis is treated with topical steroids, it will initially look better and lead to what is called, “tinea incognito”

  34. How Do We Know?

  35. Melanoma • A.One-half of the mole does not match the other half (i.e. it is asymmetric) • B.The edge (border) of the mole is jagged or irregular • C. More than one color is present in a mole • D.It is larger than 5mm in diameter (the size of a pencil eraser

  36. How Can I Determine MyPersonal Risk? • It is estimated that 1 out of 7 people in the United States will develop some form of this cancer during their lifetime. One serious sunburn can increase the risk by as much as 50%. • These early studies are coming into question. Risk determination is complex

  37. Pathologic Staging • Depth of invasion offers the greatest prognostic value in determining survival • Depth of invasion determines need for therapy up and above surgical excision

  38. Treatment • Wide excision • Regional lymph node dissection for higher stage disease • Chemotherapy for higher stage disease

  39. Psoriasis • Extensor surfaces most common • Palms and soles not commonly involved but can be. R/O Reiter Syndrome • Localized plaques may be confused with eczema or seborrheic dermatitis • Guttate form may be confused with secondary syphilis or pityriasis rosea

  40. Principles of Treatment • Control stress • Stress reduction techniques are effective in controlling flares in certain patients • Determine end of treatment • Patients perceive discoloration after clearing plaques as continued disease

  41. Principles of Treatment • Calcipotriol (Dovonex) • Discovered in 1985 by chance-Women taking Vitamin D for osteoporosis noted marked improvement in psoriasis • Vitamin D3 analogue • Inhibits cell proliferation and induces terminal differentiation • Inhibits epidermal cell proliferation • Safe and effective • Applied BID in amounts up to 100 grams per week • Rx for 6-8 weeks gives 60% improvement • Does not effect ca++ or bone metabolism

  42. Principles of Treatment • Topical steroids • Control itching • Results very gratifying early • Tachyphylaxis occurs • Skin atrophy and tangelectasias limit extensive use • Useful for treating intertriginous plaques and inflamed areas • Plastic occlusion potentiates • Diprolene, Temovate

  43. Principles of Treatment • Intralesional steroids • Kenalog 5-10 mg.Ml (atrophy with 10 mg strength) • Anthralin (Anthra-Derm) • Used only for chronic plaques • Messy stains long treatment times • Best used in combination with UVB

  44. Principles of Treatment • PUVA • Psoralens and UVA radiation in combination • Methotrexate • Cyclosporine • Retinoids • Etretinate (Tegison) • Hydrea

  45. Psoralin UVA Treatment

  46. UVB Treatment – Before and After

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