Dermatology Flashcards
Seborrheic keratosis
“stuck on”, verrucus appearance. Mots common benign tumor in the elderly. Brown or black.
Lichenification
chronic scratching causes skin growth (skin thickening)
Melanoma (always on the boards)
Most common in women, tumor marker S-100, METASTASIZES!
Risk: FHx, fair skin, actinic keratosis, outdoor work, sunburns
Superficial spreading: mc
Nodular: most aggressive
Lentigo: elderly, slow growing
Acral lentigious: most common in dark skin- palms, soles, nails- aggressive
Hyperkeratosis, pankeratosis, acantholysis, acanthosis
Hyperkeratosis: thickening of skin. Warts, corns, callouses.
Parakeratosis: thinning of the granular layer of the skin, like in psoriasis and dandruff
Acantholysis: cells lose their connections (desmosomes). Happens in pemphigus, not pemphigoid.
Acanthosis: diffuse epidermal hyperplasia, happens with insulin resistance
ABCDE
Assymetry, borders, color, diameter, elevation
Actinic keratosis
10% can change to SCC; rough, scaling appearance
Rehydration in: hypovolemia, DKA, etc
Hypovolemia: normal saline (0.9%)
DKA: 5% dextrose in hypotonic solution (they lose glucose , which pulls water out with it; need to rehydrate with both)
Case #1: woman with a large, red bump in her armpit says it came on several days ago after shaving. Dx, tx?
Ddx: *abscess (soft fluctuant mass, comes on quickly); not a sebaceous cyst (sebum from the sebaceous duct builds up, slow)
Tx: I&D with a field block
Tools: #11 scalpel and hemostat
(11s are sharp and pokey, good for poking holes in things)
Field block= diamond-shaped pattern around the lesion you are trying to remove
Aftercare: pack with iodoform gauze
If draining continues, it’s possible that the lesion was multilocular and was not drained completely
Case #2: Postaural, round, 2 cm mass, nontender
Sebaceous cyst- soft & mobile, may feel like a marble
Tx: incision and removal of the entire mass
Most appropriate anesthesia: 1% lidocaine with epi
Remove entire capsule to prevent recurrence
Suture behind the ears, remove 7-10 days (scalp)
Case #3: brown lesion on bra line, 41yo gravid female; 3mm papule with erythematous border; she has a sulfa, penicillin allergy
How to remove? Shave biopsy (want to keep tissue intact for pathologist to examine)
Which anesthetic is safe for 1st trimester pregnancy? Lidocaine
(When in doubt, just use lidocaine)
Dermatofibroma
secondary to trauma, increased fibroblasts, brown-firm like a BB
Epidermal inclusion cyst
Aka sebaceous cyst. Moveable capsule filled with keratin, sebum. Slow-growing.
Lipoma
SubQ nodules that recur. Small, moveable, rubbery.
Pilar cyst
Aka wen. An epidermal inclusion cyst on the scalp.
Hemangioma
DONT CUT IT. Especially cavernous hemangiomas.
Benign cluster of blood vessels.
One of the MC tumor in infants. Many self-resolve.
Seborrheic dermatitis
Cradle cap in children, dandruff in adults. Mildly itchy. Greasy, clear or yellow with scales.
Tx: Se+ sulfide shampoo, Zn+pyrithione
Acne vulgaris
Noninflammatory: open/closed comedones
Inflammatory: pustules, papules (<5mm), nodules (>5mm)
Avoid: B12, iodine
Tx: Zn, CU, Cr, Se, n3, VD, tea tree oil, retinoids, benzoyl peroxide, accurate (suicidality a risk, 2 forms of birth control). Clindamycin, doxycycline, OCPs
Vitaligo vs melasma
Melasma occurs during pregnancy and is hyperpigmentation
Vitaligo is an autoimmune disease that causes hypo pigmentation. Tx with Cu, vitamin D, phenylalanine
Kaposi’s sarcoma
round/oval papules or plaques, pink/red/purple on the legs, which ulcerate. Associated with AIDS and HHV8. Excision.
Solar lentigo
“liver spots”, benign, from sun exposure
Erythema nodosum
Lesion of subQ fat, usually anterior shins. Caused by sarcoid, TB, leprosy, histoplasmosis, coccidiomycosis, Crohn’s disease, cancer, NSAIDs, or idiopathic.
Elevate legs, compression, wet bandages
BCC
Most common HUMAN cancer. SLOW-growing. Mets are rare. May look pearly with a rolled border, teleangelectasia. Sun-exposed areas, upper lip. Highly curable when removed.
Arsenic exposure is a risk.
Types:
Nodular (mc), superficial, ulcerative, and pigmented
SCC
FAST-growing. May develop from actinic keratosis. Mets are common. Indurated, ulcerated, crusty, may bleed. Lower lip.
Arsenic exposure also a risk
Cellulitis
GAS in the DERMIS. Can lead to necrotizing fasciitis, erysipelas (lymph involvement, skin looks like an orange peel).
Tx: Keflex, Trimethoprim-Sulfamethoxazole
Lymphangitis
red streaking along lymph nodes
Erysipelas
strep infection of superficial lymphatics due to immunocompromised, trauma, ulceration or skin injury
Statis dermatitis
chronic venous insufficiency due to DM or being bed-ridden
Genital warts and cervical cancer
Genital warts: HPV 6, 11
Cervical dysplasia: 16, 18, 31, 33
Roseola infantum
6th disease. HHV6/7. Maculopapular rash with high fever.
Rubella
Cranial-caudal maculopapular rash with CLAD and fever
Measles
3 Cs: cough, coryza, conjunctivitis
Koplik’s spots.
Worst side effect: subacute sclerosing pan encephalitis
Impetigo
Staph or strep; honey-colored; tx is muprocin
HSV
Prodrome with itch, fever 1: oral 2: genital Antibodies arise in 4-6 weeks. Tx with lysine, avoid arginine
Herpes zoster
Shingles. Along a dermatome, neurotic pain and blisters.
Tx: levodopa, UV light, vaccine (zostavax)
Molluscum contagiosum
Viral infection, can be an STI (pox virus). Waxy, pink with central pit. Usually go away in 6-9 months
Tx: vitamin B9, salicylic acid, electrodessication or cry
Tinea versicolor (pityriasis versicolor)
Will look gold under the Woods lamp. Caused hypo pigmentation. KOH+. Tx: terbinafine, ketoconazole
Dyshydrotic eczema
Aka pompholyx. IgE reaction to nickel, etc. Weeping vesicles on hands and feet.
Pityriasis rosea
Mc in 10-20yo, occurs after URI, first you see a herald patch, may be Christmas-tree shaped. Resolved in 1-3 months. If severe, topical steroids, UV light, erythromycin o acyclovir
May be caused by HHV7
Erythema multiforme
Acute, self-limiting. Symmetrical lesions with concentric rings (target lesions). Caused by infection- HSV, mycoplasma pneumonia; drugs (sulfa, antiseizure, barbiturates, Abx, allopurinol); idiopathic (50%!)
Drug eruptions
1-3 weeks after drug (mc is 7 days after)
Can be morbiliform (maculopapular, measles-like)
Nail infections
Paronychia: infection of the nail bed, usually staph, strep or candida. warm compress, reflex
Felon: subQ abscess under nail bed, can occur after paronychia
Onchomycosis (Tinea unguium): nail fungus. Tx with meulalucca, terbimafine anti fungal
Pemphigus vulgaris vs bullous pemphioid
PemphiguS: Superficial. 40-60yo. + Nikolsky (Asboe-Hansen) sign, blister will spread. Can be deadly. Intraepidermal bullae with anti-epithelial cell Abs against desmosomes (anti-desmoglein-3 IgG). Type II hypersensitivity. Tx: steroids, methotrexate
PemphigoiD: Deep. 60-80yo. Less serious. Blister intact in sub epidermal space. Usually flexors/trunk. Linear deposition of anti-basement membrane IgGgs. Also Type II reaction.
Erythema migrans
Bullseye
From a tick bite- B. burgdorferi
Stevens-Johnson Syndrome
Toxic Epidermal Necrolysis
Emergency!
Flu-like symptoms, blisters, pneumonia, sepsis and organ failure.
Cause: lamotrigine, carbamazepine, allopurinol, sulfonamide antibiotics, and nevirapine (HIV antiviral); Mycoplasma pneumoniae, CMV, and HIV
Tx: no accepted standard. Fluids, analgesics, ophthalmologist consult (can affect eyes)
May be due to CYP variant that slows processing of some drugs.
SLE
Discoid or malaria rash, worse in the sun, IgG/IgM
Granuloma annulare
Chronic skin condition, circular small flesh papules, increase in size, hands and feet. Idiopathic, but may be associated with endocrine disease (thyroid disorders and diabetes)
Contact dermatitis
Irritant or allergic
Delayed hypersensitivity reaction
Dermatitis herpetiformis
Celiac disease
IgA deposits cause itchy papules and vesicles
Atopic derm
Eczema, IgE reaction, eosinophilia, asthma, hayfever associated
Effects flexor surfaces
Tx: Psorinum, sulphur, vitamin C, steroids, emollients, tacrolimus 0.03% (calcineurin inhibitor), dupilimab if severe (inhibits IL4 and IL13)
Psoriasis
Auspitz phenomenon, Kobner’s phenomenon
Nail pitting, arthritis
Areas of friction like scalp, extensor surfaces
Types: plaque (mc), guttate (GABHS or viral trigger), pustular, inverse, erythrodermic
Lichen simplex
Red, scaling, itching constantly. can be unilateral.
Lichen planus
Wicham straie 5 Ps (pruritus, planar (flat), purple, polygonal papules) Palms and wrists Associated with hepatitis C Mucosal lesions, nail involvement Tx: steroids, immunosuppressants
Hairy leukoplakia
white, painless patches on the tongue that CANT be scraped off. Caused by EBV, usually in HIV patient.
Infestations
Black widow spider: NEUROtoxic, painless bite
Brown recluse: NECROtoxic, painful
Scabies: serpiginous lesions, worse at night, don’t extend above the neck, common in wrist creases. Tx: permethrin.
Pediculosis (lice): tx with permethrin, washing clothes and bedding in hot water
Necrotizing fasciitis
Infection of the fascia which secondary necrosis of the subQ. Type I: polymicrobial. Type II: beta-strep
Will see increase in serum CK. IV penicillin and clindamycin. Surgical debridement.
Acanthosis nigrans
Dark velvety appearance of skin on the posterior neck and flexural folds. Associated with DM, obesity, CA, insulin resistance.
Most common human cancer
BCC
Slow growing, doesn’t often met, prognosis good if caught early
