Derm 1 Flashcards
What should be considered in abscesses in the lower back and perineal regions?
Anaerobic bacteria
A patient comes in concerned about recurrent abscesses in the axilla, groin, and perineum. What is this? What causes it? Treatment?
Hidradenitis suppurativa
Caused by chronic follicular occlusion and apocrine gland inflammation
Often antibiotics and surgery
What causes dry gangrene?
Gradual necrosis of skin from vascular insufficiency…features hard, dry skin
What causes wet gangrene?
Vascular obstruction or infection –> swelling and blistering
Kid comes in with yellow crusted lesions. What is this? What causes it? Treatment?
Impetigo
Staph a or GAS
Wash affected area
Erythromycin, cephalosporin, or topical antibiotic
What causes acne vulgarism? Treatment
Propionibacterium acnes
Topical retinoids (first line; decrease sebaceous gland activity) Antibiotics (topical or oral) Oral contraceptives (decrease androgen production) Oral isotretinoin (watch liver and pregnancy...two negative urine tests before starting treatment)
What can cause acne vulgaris, usually seen in adolescents, in adults?
Corticosteroid use and androgen production
When are chickenpox and shingles no longer infective?
When lesions crust over
During a pelvic exam (or testicular exam) you notice shiny papules with central umbilication. What are the lesions? What should you be concerned about?
Molluscum contagiosum
HIV
A patient comes in with itchy feet that is worse after a hot shower. What should be looked for? Treatment?
Mites and eggs on skin scraping under microscope
Permethrin cream
A patient comes in with salmon-colored, light brown, or hypopigmented macules, with evidence of scaling where scraped, on chest and back. What is this? What causes it? How is it diagnosed? Treatment?
Tinea versicolor (pityriasis versicolor)
Caused by Malassezia furfur
Diagnosed by short hyphae and spores on KOH prep
Topical antifungal for several weeks or oral ketoconazole for 1-5 days
Patient presents with pruritic, erythematous, scaly plaques with central clearing. What is this? What causes it? How is it diagnosed? Treatment?
Tinea…body part
Microsporum
Trichophyton
Epidermophyton
KOH prep shows hyphae
Topical antifungal for multiple weeks…oral antifungal for resistant
A patient presents with pruritic, painful erythematous plaques with pustules in a skin crease. What is this? What causes it? How is it diagnosed? Treatment?
Intertrigo
Candida albicans
KOH prep shows pseudohyphae
Topical antifungal agent
Topical corticosteroid
Are most allergic contact dermatitis caused by type I or type IV hypersensitivity reactions?
Most are type IV (lymphocyte activity several days after 2nd+ exposure)
Type I is caused by mast cell degranulation (urticaria)
A patient was recently started on a drug for some reason or another. Now presents with malaise, myalgia, pruritus with a rash (macule, plaques, or vesicles; target lesions). What is going on? What would be seen on labs/biopsy?
Erythema multiforme
Increased eosinophils
Increased lymphocytes and necrotic keratinocytes
What drugs are associated with erythema multiforme? What kind of infections? What else?
PCN, Sulfonamides, NSAIDs, OCTs, Anticonvulsants
HSV and mycoplasma pneumonia
Vaccinations
Stevens-Johnson is essentially really bad erythema multiforme. What is present in SJS that isn’t seen with EM? What symptoms are more common? Treatment?
Skin sloughing, oral lesions
Myalgia, fever, N/V, oral pain, eye pain
Stop offending agent, corticosteroids, analgesics, IV fluids…often treated in burn unit
What is seen with Toxic Epidermal Necrolysis (TEN)?
Significant skin sloughing
Full-thickness epidermal necrosis
Decreased WBC, Hgb, and Hct
Increased ALT and AST
An adolescent or an infant presents with pruritic, erythematous plaques with yellow, greasy scales. What is going on? Treatment?
Seborrheic dermatitis (cradle cap in infants)
Shampoo containing selenium, tar, or ketoconazole (for scalp)
Topical corticosteroids and antifungals (other areas)
A patient presents with something that looks/sounds like eczema, but eczema isn’t on the list. What is another name for eczema?
Atopic dermatitis
Erythematous rash with silvery scales that bleed when picked off. What is it? How is it treated?
Psoriasis
Topical corticosteroids, tar, retinoids, tacrolimus, or antifungal; phototherapy, methotrexate, cyclosporine, anti-TNF drugs
A patient comes in with an “Christmas tree” eruption of oval erythematous papillose covered with white scales on chest/back/extremities and says that a few days before it had been a single round lesion. What is this? How is it treated?
Pityriasis rosea
Often self limited
Patient has painful erythematous nodules over her tibia. What are they? What is it associated with? Treatment?
Erythema nodosum
Delayed immunologic reaction to infection, collagen-vascular diseases, IBD, drugs
Self-limited
Patient comes in with painful, fragile, blisters in oropharynx and on chest, face, and/or perineal regions. On exam, the blisters rupture easily. What is going on? What causes it? Treatment? Complications?
Pemphigus vulgaris
Autoantibodies to adhesion molecules in epidermis
Corticosteroids, azathioprine, or cyclophosphamide
Sepsis, high mortality w/o treatment
Osteoporosis (chronic corticosteroid use)
An older patient (>60yo) comes in with widespread blisters (especially on flexor surfaces and perineal region) that itch. On exam, you notice that erosions have formed where blisters have ruptured. What is going on? What causes it? Treatment?
Bullous pemphigoid
Autoantibodies to epidermal basement membrane
Oral or topical corticosteroids or azathioprine
A patient with chronic blistering lesions on sun-exposed skin (with lots of scars), hyperpigmented skin, and facial hypertrichosis (hair). What is going on? What causes it? What is it associated with? Treatment?
Porphyria cutanea tarda
Deficiency of hepatic uroporphyrinogen decarboxylase…part of heme metabolism
Liver disease
Periodic phlebotomy, low dose chloroquine or hydroxychloroquine; sunscreen use; avoidance of triggers (alcohol, estrogens, tobacco, iron supplements)
A person comes in with a rough papule with yellow-brown scales. What is it? Biopsy? Treatment? Complication?
Actinic keratosis
dysplasia of epithelium…deeper epithelial cells show variation in shape and nuclei
Topical 5-FU or imiquimod, or cryotherapy
SCC
A person comes in concerned about a pearly papule with telangiectasia or central herniation. What could it be? Biopsy? Treatment?
BCC (most common type of skin cancer)
Basophilic-staining basal epidermal cells arranged in palisades
Excision, radiation, or cryotherapy
Which melanoma grows vertically…making it rapidly invasive and difficult to detect?
Nodular melanoma
Where do acral lentiginous melanomas form?
Palms, soles, or nail beds
Which melanoma has a long lasting in situ stage before vertical growth?
Lentigo maligna
