Dermatology Scenarios Flashcards
Erythema with yellowish scale-forming plaques on the eyebrows, nasolabial folds, glabella, and presternal area best describes:
a) bacterial folliculitis
b) allergic contact dermatitis
c) rosacea
d) seborrheic dermatitis
d: This is a classic distribution pattern for seborrheic dermatitis, a common, chronic inflammatory dermatitis associated with Pityrosporum ovale as well as genetic and environmental factors. Bacterial folliculitis presents as dome-shaped pustules with small erythematous halos arising in the center of hair follicles. Allergic contact dermatitis is characterized by vesicles, edema, erythema, and pruritus. Rosacea presents as eruptions of erythema, telangiectasias, pustules, and papules localized to the face.
A 36yo pt reporting sudden hair loss is found to have a round, well-circumscribed, 3cm area of alopecia on the parietal scalp area with exclamation point hair. The most likely dx is:
a) anagen effluvium
b) androgenetic alopecia
c) alopecia areata
d) tinea capitis
c: Alopecia areata is an autoimmune process presenting as localized, well-circurmscribed loss of air in oval or round patterns without visible evidence of inflammation, most commonly on the scalp with exclamation point hair at the periphery of alopecia. Tinea captitis is uncommon in adults. It has “black dots” in the area of alopecia from broken-off hair, also with scale and possibly inflammation. There also may be adenopathy
A Tzanck smear demonstrating multinucleated giant cells indicates which of the following conditions?
a) scabies
b) tinea versicolor
c) impetigo
d) herpes simplex
d: The Tzanck smear is a microscopic examination of cells obtained from the base of vesicles and bull for multinucleate giant cells seen in herpes simplex, herpes zoster, and varicella. Scabies is dx with a scabies prep, a microscopic examination for mites, scybala (fecal pellets), or eggs. Tinea versicolor is a dermatophyte infection dx with a KOH test looking for a hyphae and spores in a classic spaghetti-and meatballs* pattern. Impetigo is caused by a streptococci and/or staphylococci typically dx by the clinical presentation, but culture and sensitivity tests an isolate the causative organisms.
An acute eruption of violaceous, pruritic, polygonal, shiny, flat-topped papillose involving the flexor surfaces is suggestive of which of the following?
a) lichen planus
b) pityriasis rosea
c) psoriasis
c) seborrheic dermatitis
a: Lichen planus is an inflammatory reaction pattern of unknown etiology, with characteristic “five P” clinical features: pruritic, planar (flat), polyangular/polygonal, purple (violaceous) papules. Pityriasis rose is typically confined to the trunk, beginning with a single red oval plaque that is followed by a number of similar smaller plaques with spontaneous resolution in 4-8 weeks. Psoriasis is a papulosquamous disease commonly presenting on scaly plaques involving the elbows, knees, and scalp. Seborrheic dermatitis is a common, chronic inflammatory disease commonly seen on the scalp and scalp margins, eyebrows, nasolabial folds, and presternal areas
Bites that typically reveal a central blue color of impending necrosis with a surrounding white area of vasospasm and a peripheral red halo of inflammation are associated with:
a) scabies
b) black widow spiders
c) brown recluse spiders
d) deer ticks
c: Brown recluse spider bites in fatty areas such as thighs and buttocks can become necrotic within 4 hours; with a rapidly expanding blue-gray halo around the puncture site surrounded by a white area of vasospasm and peripheral red red halo of inflammation. Scabies lesions are pleomorphic and often vesicular, pustular, or excoriated with linear, curved, or S-shaped burrows. Black widow bites result in slight swelling with small red fang marks. Deer tick lesions can present as a small papule with slowly enlarging ring, a bluish red nodule, or an atrophic plaque.
Velvety, hyperpigmented, papillomatous lesions of the neck, axillae, and groin would warrant what further testing?
a) KOH test of skin scrapings
b) fasting blood sugar
c) mineral oil skin scraping
d) CXR
b: Acanthosis nigricans is commonly associated with obesity, insulin resistance, and DM. A fasting blood sugar is a first step in screening pts for insulin resistance. KOH of skin scrapings is used to look for hyphae and spores indicating a fungal infection or tinea versicolor. While tinea versicolor is velvety and can be hyper pigmented, it is not papillomatous. Mineral oil skin scrapings are used to look for the mites of scabies. Scabies can occur in the axillae but appear as erythematous papules or nodules. A CXR would be used to look for pulmonary changes associated with cutaneous findings, such as sarcoidosis. Acanthosis nigricans is not associated with pulmonary changes.
A pt known to have allergic rhinitis and asthma presents with chronic pruritic inflammatory lesions of the flexor surfaces, wrists, and dorsal ares of the feet. The lesions are excoriated and lichenified with crusted patches and plaques. The most likely dx is:
a) nummular eczema
b) psoriasis
c) seborrheic dermatisis
d) atopic dermatitis
d: Atopic dermatitis often occurs in association with a family or personal history of atopy, to include allergic rhinitis, asthma, and eczema. It is characterized as the “itch that rashes” and is associated with dry skin, ichthyosis vulgarism, keratosis pilaris, sensitivity to wool, and hyperlinear palmar creases. Psoriasis is a papulosquamous disease commonly presenting as scaly plaques involving the elbows, knees, and scalp. Nummular eczema presents as chronic, coin-shaped plaques with small papules and vesicles on an erythematous base, typically seen on lower legs of older men in winter months. Seborrheic dermatitis presents as erythema with yellowish scale-forming plaques on the eyebrows, nasolabial folds, glabella, and presternal area.
Which of the following diseases can affect the skin, nail, and joints?
a) erythema nodosum
b) psoriasis
c) pityriasis rosea
d) lichen planus
b: In addition to erythematous scaly papules and plaques, psoriasis may present with oil spots, nail pitting, and onycholysis. Psoriatic arthritis occurs in 5-8% of those affected with psoriasis. Erythema nodosum is an inflammatory nodular pattern of panniculitis typically involving only the lower extremities. Pityriasis rosea is an epidermal papulosquamous disorder typically confined to the trunk, with NO nail or joint involvement. Lichen planus is characterized as an inflammatory reaction pattern with mucous membrane, nail, scalp, and cutaneous lesions but no associated joint involvement.
Using the “rule of nine” to calculate body surface area, what would the percentage of burned area be in an adult pt with second-degree burns involving the entire right arm, the anterior chest and abdomen, and the entire right leg?
a) 27
b) 36
c) 45
d) 52
c: The anterior chest and abdomen are 18%, the entire right leg is 18%, and the entire right arm is 9% for a total body surface area of 45%.
Mupirocin (Bactroban) ointment is indicated for the tx of mild to moderate
a) impetigo
b) ecthyma gangrenosum
c) tinea pedis
c) cellulitis
a: Mupirocin is the first topical abx approved for the tx of impetigo. Tinea pedis is a dermatophyte infection tx with antifungals. Cellulitis typically requires tx with oral or parenteral abx.
Organ transplant recipients have a significantly increased risk for developing
a) squamous cell carcinoma
b) erythema multiforme
c) bullous pemphigoid
d) pseudomonas folliculitis
a: Immunosuppressive agents required following organ transplant greatly increase the risk for developing squamous cell carcinoma. Erythema multiforme, a reaction pattern of idiopathic, drug, and infectious origin, is unrelated to organ transplant immunosuppression, as is bullous pemphigoid, an autoimmune sub epidermal blistering disease. Pseudomonas folliculitis is an acute skin infection that follows exposure to contaminated water and is also known as “hot tub folliculitis”
A predisposing condition for recurrent cellulitis of the lower extremity is:
a) onychomycosis
b) tinea pedis
c) verruca vulgaris
d) erythema nodosum
b: Fungal infection of the interdigital spaces can result in breaks in the dermal barrier, permitting bacterial entry through the skin, and requires careful examination of the feet in lower extremity cellulitis. Onychomycosis typically involves the nail plate and not the surrounding soft tissue. Common warts (verruca vulgarism) are not likely to lead to breaks in the dermis because they arise from the epidermis. Erythema nodosum, a hypersensitivity reaction to a variety of antigenic stimuli, typically present as erythematous nodules over the anterior shin area and is not associated with the development of cellulitis.
A pt presents with complaints of the development of a slate-gray hyperpigmentation on the lower extremities. Which of the following agents is most likely responsible?
a) minocycline (Minocin)
b) erythromycin (E-mycin)
c) tremethroprim-sulfamethoxazole
d) Naproxen (Aleve)
a: Slate-gray hyperpigmentation is an adverse effect of minocycline. Cutaneous side effects of erythromycin typically include urticaria, maculopapular rash, erythema, and acute generalized exanthematous pustulosis (AGEP).
A 12yo girl presents with complaints of pruritis of the scalp for 2 weeks that started at the occiput and post auricular areas but has now spread. What is the most likely dx?
a) psoriasis
b) seborrheic dermatitis
c) pediculosis capitis
d) tinea capitis
c: Pediculosis capitis (head lice) begins most commonly at the occiput and post auricular area where grayish white, oval-shaped nits are seen adhered to the hair shaft. Psoriasis presents with well-demarcated, erythematous plaques with silvery white scale. Seborrheic dermatitis presents with diffuse erythema with a greasy yellow scale throughout the scalp. Tinea captitis appears as an area of alopecia with scale and broken off hair or “black dots”
A 22yo pt presents with multiple, flat, round, light-brown lesions measuring 1-5mm. Several are noted to form a linear pattern. The most likely dx is:
a) lichen planus
b) verruca plana
c) seborrheic keratosis
d) syringomas
b: Flat warts or verruca plan are light brown or flesh-colored papules ranging form 1 to 5 mm in diameter. Because the virus spreads with scratching or shaving, a linear pattern forms. Lichen planus lesions are pruritic, planar (flat), polyangular/polygonal, purple papules, generally seen on the solar aspects of the wrist and forearm as opposed to the dorsum. Seborrheic keratoses range from 2mm-3cm, can be tan, brown, or black in color, can appear on the dorm of the hands, but do not form a linear pattern secondary to trauma.
