Term
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Definition
Genetic, systemic, inflammatory (T CELL MEDIATED); can be triggered by environmental/social conditions (strep, trauma, stress, diet, rare light sensitive manifestation)
Red macules -> non-scaly papules -> scaly papules -> plaques
Clinical exam: silvery scales, well demarcated pink patches, commonly involves elbows and knees, scalp, behind ear; see guttate/drop-sized papules with post-strep manifestation; nail changes - pitting, oil drop sign, onycholysis
DDX: Dermatitis, Dandruff (scalp), fungal infection (onycholysis)
Prognosis/Course: good, but erythroderma (widespread skin invovlement) can be fatal, can get psoratic arthritis (involving DIP joints), pustular psoriasis (acceleration of course with many neutrophils), linear plaques (Koebner phenomenon) from external trauma
Histology: regular epidermal hyperplasia due to increased epidermal cell proliferation (shortened lifespan), parakeratosis, hypogranulosis, dilated capillary loops, munro microabscesses (pustular form)
Rx: sunlight/UVA and UVB (some exceptions), fish and omega 3 oils, topical steroids, coal tar, calcipotriene, retinoids, methotrexate, cyclosporine, biologics |
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Term
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Definition
Inflammatory process - idiopathic or induced by drugs, Hep C
Flat pink macules -> violaceous papules with polygonal outline and flat top (goes away after a year) -> persistent rubbing -> hypertrophic lichen planus (may last years)
Clinical Exam: favors flexual surfaces of skin and buccal mucosa; polygonal, purple, pruritic, papules; can form plaques; can see permanent alopecia if scalp follicles involved (pseudopelade of brocq), destroyed nail matrix (anonychia); Wickham's striae (overlying network of white lines)
Histology: hypergranulosis, inflammation in a band between dermis and epidermis, sawtoothing of epidermis
Can see extensive, ulcerative form on palms, soles, mucous membranes = erosive lichen planus
Rx: topical steroids, prednisone, retinoids, UVA |
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Term
| Psoriasiform Dermatitis - Lichen Simplex Chronicus |
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Definition
Aka circumscribed neurodermatitis - eruption caused by habitual itching of a single localized area (pts get great pleasure out of itching)
Clinical Exam: papular lesions (red, brown, hard, dome shaped, crusted/warty surface), intense itching
Histology: irregular epidermal hyperplasia
Rx: steroids, antihistamines, anesthetics, behavioral modification |
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Term
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Definition
Benign, self-limited (6 wks), papulosquamous eruption (unknown etiology - maybe viral? more frequent in spring and fall)
Clinical Exam: Single 2-10cm lesion (HERALD PATCH) appears and then get eruption of smaller lesions; fine, wrinkled scales at border of plaque (collarette scale); christmas tree distribution
Histology: superficial perivascular/interstitial lymphocytic infiltrate, edema, epidermal hyperplasia
Rx: recognize dx and reassure pt, antihistamines and steroids to control itch, UVB, benign neglect! |
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Term
| Contact Dermatitis (Allergic) |
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Definition
Delayed type IV hypersensitivity rxn (common agents - poison ivy/oak, nickel, perfume, soap, detergent, cosmetics) - skin rash that develops from contact with previously encountered agent
Clinical Exam: multiple tiny vesicles; red, swollen, warm, itchy (may see fever, lymphadenopathy, malaise) - Dx with patch testing
Histology: spongiosis (tissue edema), rupture of keratinocytes, widening of extracellular spaces |
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Term
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Definition
AKA Eczema; relapsing, inflammatory, immune mediated (IgE) immediate hypersensitivity reaction; children may outgrow it; associated with asthma, allergic rhinitis
Clinical Exam: itching, lichenfication, dry, scaly patches and plaques in flexural areas
Histology: intracellular edema, exocytosis of lymphocytes
Rx: emollients, steroids, antihistamines, UVB, avoid scratching and secondary infection |
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Term
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Definition
Pox virus infection - can be an STD in adults; seen more in children and HIV population
Clinical Exam: skin-colored, smooth, dome-shaped papules with central umbilication and filled with cheesy material; numerous lesions may signal immunocompromise
Histology: large basophilic and eosiniphilic inclusion bodies in keratinocyte cytoplasm (molluscum bodies)
Rx: cryotherapy, TCA currettage, examine and treat any sexual partners |
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Term
| Verruca/Condyloma/Accuminata |
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Definition
HPV-related (infects keratinocytes)
Clinical Exam: papules on skin and mucous membranes, cauliflower-like warts, may see mosaic warts with punctate hemorrhages (DDX: squamous cell carcinoma)
Histology: virally-infected keratinocytes
Rx: cryotherapy, canthrone, TCA, pulse dye laser therapy, bleomycin |
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Term
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Definition
Infectious disease, caused by yeast (Malassezia furfur) proliferating in stratum corneum
Clinical Exam: white or light brown macules on trunk (hypopigmentation), get dust-like scales if you scratch it
Dx: scrape scales from lesion, place in KOH and examine for spores and hyphae - "spaghetti and meatballs appearance"
Rx: localized - topical antifungals, selenium sulfide shampoo; widespread - ketoconazole, fluconazole, itraconazole; wash clothes to get rid of yeast |
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Term
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Definition
Infection process caused by superficial fungi
Clinical Exam: multiple possible morphologies, many only involve 1 hand, centered in follicles, seen more on scalp, inguinal region, hands, feet, nails, dermatophytes (athelete's foot!)
Dx: KOH prep/culture (see hyphae)
Rx: Antifungals, keep area dry, powder |
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Term
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Definition
Caused by corynebacterium minutissiumum, common in diabetics and warm climates
Clinical Exam: slowly enlarging pink/brown patch that dominates flexor surface, asymptomatic
Dx: bacterial make porphyrins - will fluoresce!
Rx: erythromycin |
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Term
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Definition
Infectious, caused by mite (sarcoptes scabiei - lays eggs in skin); get itching (worse at night and with hot water) due to hypersensitivity rxn to mite feces
Associated with unclean conditions, spread from person-person
Clinical Exam: papules, vesicles, nodules (digital interwebs, breasts, genitals, chest)
Dx: KOH prep, look for burrows and lesions on areolas or penis
Rx: Ivermectin, permethrin; be sure to treat contacts |
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Term
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Definition
Seen in immunocompromised, pts with decreased cutaneous sensation, or those who can't scratch effectively
Extensive crusted lesions with huge numbers of mites
AKA crusted scabies |
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Term
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Definition
Immune-mediated disorder from drugs (PCN, sulfa, phenytoin), infection (HSV, mycoplasma), vaccination or malignancy
Clinical Exam: Raised, erythematous plaques with TARGET PATTERN
Several classifications - EM major, Stevens-Johnson Syndrome, Stevens-Johnson Syndrome/TEN overlap, Toxic Epidermal Necrolysis
Histology: superficial, perivascular lymphocytic infiltrate; epidermal necrosis - necrotic keratinocytes, subepidermal blisters with lymphocytes, basal vacuolar change (dermis/epidermis border) |
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Term
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Definition
Benign neoplasm of epidermal keratinocytes
See hyperpigmented papules/plaques (appear to be "stuck on"), in middle aged + elderly (NOT children)
DDX: verruca, actinic keratosis, nevi, melanoma, basal cell carcinoma
Horn cysts observed when lesion is pushed down
Paraneoplastic sign: when numerous ones acutely erupt = sign of Lesar-Trelat; signals an underlying malignancy (gastric carcinoma) |
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Term
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Definition
Premalignant epidermal neoplasm caused by UV exposure; presents as a rough, erythematous plaque or papule on sun-damaged skin
Fair complexions at higher risk!
Dx: clinical or by biopsy
Rx: sunprotection, 5-fluorouracil, cryosurgery, chemical peel
Pathology: epidermal atrophy, atypical keratinocytes confined to lower third of epidermis, hyperchromic nuclei |
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Term
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Definition
Malignant neoplasm of keratinocytes caused by UV exposure/ionizing radiation, X-rays, and chemical carcinogens; can also develop from lesions of DLE, Lichen Planus, draining sinuses, or old burn scars
Second most common skin cancer
Can be in situ or invasive; well or poorly differentiated
Appears as a hyperkeratotic, indurated
plaque or nodule (scaling and crusting) that bleeds or ulcerates and becomes painful
May see malignant keratinocytes in dermis and vessels (where they don't belong)
Rx: surgery, MOHS, sunprotection, radiation |
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Term
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Definition
Malignant, poorly-healing plaque/papule with a pearly, translucent character, overlying telangiectasia, ulceration and/or crusting; may bleed; usually due to sun exposure
Most common skin cancer!
Slow growing, generally not metastatic but can cause local damage, usually don't do serious harm
Rx: surgical (ED+C, excision), MOHS, radiation, photodynamic therapy, immunotherapy -> high cure rate
Pathology: picket fencing, basophilic cells palisading with retraction, uniform size, polygonal, variable mitotic rate, oval nuclei with inconspicious nucleoli
Keratotic and morphea forms more aggressive |
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Term
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Definition
Benign neoplasms of modified melanocytes of neural crest origin
Different kinds: common acquired, congenital, blue nevi, Spitz nevi
See "nests" in epidermis
Dysplastic nevi may become melanoma |
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Term
| ABCDEs of Skin Evaluation |
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Definition
A - Asymmetry (should be symmetrical)
B - Border (smooth and distinct is good)
C - Color (one uniform color is good; red, white, blue or black is bad)
D - Diameter (should be less than 5mm)
E - Evolving and Erythema (should have no erythema, and should not be changing)
ex: Nevi will pass ABCDEs, Melanoma will not |
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Term
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Definition
Aggressive melanocytic malignancy; risk factors include sun exposure, fair skin, family history, xeroderma pigmentosa, dysplastic nevi, lots of nevi
Pathology: melanocytes with marked atypia (hyperchromic nuclei, vacuolated cytoplasm, prominent nucleoli, pleomorphism) w/ pagetoid spread
Use ABCDEs to evaluate
Biopsy - always get everything out, never do shave biopsies (then you can't gauge thickness)
SINGLE MOST PROGNOSTIC INDICATOR IN MALIGNANT MELANOMA IS TUMOR THICKNESS (DEPTH OF INVASION) |
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