Dermatology Flashcards
A young, obese patient presents with a velvety rash in the axilla and back of the neck (pictured below). What pathologic condition is likely associated with this rash?
Insulin resistance
this rash is consistent with acanthosis nigricans
Cellulitis is typically caused by […] (nonpurulent) or […] (purulent)
Cellulitis is typically caused by Streptococcus pyogenes (nonpurulent) or Staphylococcus aureus (purulent)
Diagnosis of Tinea versicolor is confirmed with […], which demonstrates a classic “spaghetti and meatballs” appearance.
Diagnosis of Tinea versicolor is confirmed with KOH preparation, which demonstrates a classic “spaghetti and meatballs” appearance.
Do cherry hemangiomas typically regress spontaneously?
No
Patients that have sudden onset of multiple seborrheic keratoses should be evaluated for underlying […].
Patients that have sudden onset of multiple seborrheic keratoses should be evaluated for underlying internal malignancy (e.g. GI).
Leser-Trelat sign
Porphyria cutanea tarda is caused by a deficiency of the enzyme […].
Porphyria cutanea tarda is caused by a deficiency of the enzyme uroporphyrinogen decarboxylase.
may be detected as elevated plasma or urine porphyrin levels
Seborrheic dermatitis is associated with HIV and central nervous system disorders, especially […].
Parkinson disease
Squamous cell carcinoma is characterized histologically by invasive cords of squamous cells with […].
Squamous cell carcinoma is characterized histologically by invasive cords of squamous cells with keratin pearls.
Squamous cell carcinoma is the most common malignancy of the […] lip.
Squamous cell carcinoma is the most common malignancy of the lower lip.
versus basal cell carcinoma, which typically affects the upper lip
The diagnosis of tinea corporis is confirmed with KOH preparation of skin scrapings demonstrating […].
The diagnosis of tinea corporis is confirmed with KOH preparation of skin scrapings demonstrating segmented hyphae.
The major risk factor for development of actinic keratosis is chronic […].
The major risk factor for development of actinic keratosis is chronic sun exposure.
Vitiligo is often associated with other […] conditions.
Vitiligo is often associated with other autoimmune conditions.
e.g. pernicious anemia, autoimmune thyroid disease, type 1 diabetes, primary adrenal insufficiency, etc.
What antibiotic is frequently prescribed for treatment of acne and associated with photosensitivity as an adverse reaction?
Doxycycline
manifests as exaggerated sunburn reactions with erythema, edema, and vesicles in sun-exposed areas
What are the “ABCDEs” of malignant melanoma?
A: […]
B: […]
C: […]
D: […]
E: […]
What are the “ABCDEs” of malignant melanoma?
A: asymmetric shape
B: border irregularity
C: color variegation
D: diameter > 6 mm
E: evolving
What dermatologic pathology is characterized by widespread thinning of the hair with normal appearing scalp and hair shafts, typically after a stressful event?
Telogen effluvium
e.g. weight loss, pregnancy, major illness; characterized by a positive hair pull test
What is the first-line treatment for mild inflammatory acne vulgaris?
benzoyl peroxide + topical retinoids
What is the first-line treatment for non-inflammatory comedonal acne vulgaris?
Topical retinoids
may add an organic acid preparation (e.g. salicylic acid) if initial therapy fails
What is the first-line treatment for patients with bullous pemphigoid?
High-potency topical glucocorticoids (e.g. clobetasol)
What is the likely causative organism in a patient that presents with the rash below?
Poxvirus
this patient has molluscum contagiosum (skin-colored, umbilical papules)
What is the likely diagnosis in a middle-aged patient that presents with a greasy-looking, yellowish, scaly facial rash (pictured below) and increased dandruff?
Seborrheic dermatitis
predominantly affects the scalp and face, especially areas with numerous sebaceous glands
What is the likely diagnosis in a middle-aged patient that presents with the lesions below?
Cherry angioma
most common benign vascular tumor in adults
What is the likely diagnosis in a patient living in a nursing facility that presents with a 2 x 1 cm skin ulcer overlying the sacral region?
Pressure (decubitus) ulcer
What is the likely diagnosis in a patient that develops numerous pruritic, erythematous papules with scattered vesicles/pustules on the finger webs, palms, and wrist creases (pictured below)? The patient also has numerous excoriations on the wrist.
Scabies
What is the likely diagnosis in a patient that noticed hypopigmented skin lesions on her trunk after returning from a summer vacation in Florida (pictured below)?
Tinea versicolor (due to Malassezia infection)
What is the likely diagnosis in a patient that presents with a 2 x 1 cm pigmented lesion on the abdomen (pictured below)? The lesion has increased in size over the past 6 months.
Malignant melanoma
this lesion meets all the ABCDE criteria for malignant melanoma
What is the likely diagnosis in a patient that presents with diffusely rough, dry, and scaly skin? The symptoms are worse in the winter, and symptoms of dry skin have been present for most of the patient’s life.
Ichthyosis vulgaris
chronic, inherited skin disorder characterized by diffuse dermal scaling; treatment includes topical emollients, keratolytics, and topical retinoids
What is the likely diagnosis in a patient that presents with facial erythema, flushing, and telangiectasias? The flushing is precipitated by alcohol and hot drinks.
Rosacea
What is the likely diagnosis in a patient that presents with fever, mucosal lesions, and a desquamating rash on the trunk/thighs (pictured below)? The patient was prescribed TMP-SMX one week ago.
Stevens-Johnson syndrome/Toxic epidermal necrolysis
depends on the percentage of total body surface area involves (see table); patients often have an influenza-like prodrome
What is the likely diagnosis in a patient that presents with pruritus and the rash below? A punch biopsy shows linear IgG and C3 deposits at the dermal-epidermal junction.
Bullous pemphigoid
What is the likely diagnosis in a patient that presents with the lesion below?
Squamous cell carcinoma
typically appears as an enlarging nodule in sun-exposed areas that can become keratinized and ulcerate; may also cause regional neurologic symptoms
What is the likely diagnosis in a patient with a firm, mobile nodule on the back (pictured below)? The nodule does not change shape when pinched at the edge. The patient had a similar bump in the same location months ago, which spontaneously resolved.
Epidermal inclusion cyst
benign nodule containing squamous epithelium that produces keratin; may present as a dome-shaped, firm, freely movable cyst or a nodule with a central punctum (seen below)
What is the likely diagnosis in a patient with a history of SLE that presents with uniform-appearing, erythematous papules across the back, shoulders, and upper arms? The papules appear to be in same stage of development and do not have associated comedones.
Drug-induced acne (e.g. secondary to glucocorticoid use)
What is the likely diagnosis in a patient with a lesion on the foot (pictured below)? The lesion is non-tender, firm, hyperpigmented, and has a central dimple in the center when pinched at the edges.
Dermatofibroma
most commonly occurs on the lower extremities
What is the likely diagnosis in a patient with a rash that began as small papules and progressed to erythematous plaques with oozing yellow fluid (image below)? The patient was cleaning bushes around the house a few days prior to rash formation.
Allergic contact dermatitis
likely due to urushiol produced by Toxicodendron (poison ivy/oak/sumac)
What is the likely diagnosis in a patient with an intensely pruritic and burning rash (pictured below)? The patient has also experienced ocassional diarrhea and weight loss.
Dermatitis herpetiformis
due to IgA autoantibodies against epidermal transglutaminase
What is the likely diagnosis in a patient with painful mouth ulcerations and scattered, large painful blisters on the trunk and extremities? Light rubbing of uninvolved skin causes easy separation of the epidermis. Punch biopsy shows IgG and C3 deposits in a net-like pattern.
Pemphigus vulgaris
What is the likely diagnosis in a patient with the rash pictured below? It is painful and has been present for months.
Hidradenitis suppurativa
due to occlusion of folliculopilosebaceous units; commonly affects intertriginous skin areas (e.g. axilla, groin) and can be complicated by sinus tracts, comedones, and scarring
What is the likely diagnosis in a patient with well-circumscribed and raised erythematous plaques with intense pruritus (pictured below)? The rash occurs episodically, approximately 2 - 3x/day, with each episode lasting about 6 - 8 hours.
Urticaria
What is the likely diagnosis in a sexually active college student with the rash below? It is painful and associated with low-grade fever.
[…]
Herpetic whitlow (secondary to HSV infection)
What is the likely diagnosis in a young adult patient that presents with the foot rash below? The lesions are painful with walking and standing.
[…]
Plantar warts (due to HPV infection)
What is the likely diagnosis in a young patient with a history of hepatitis C that presents with painless, pruritic vesicles and erosions on the dorsum of both hands? The patient has a history of “fragile skin”, with minimal trauma causing superficial erosions that heal with scarring.
[…]
Porphyria cutanea tarda
PCT is frequently associated with hepatitis C and manifests as photosensitivity with blisters and skin fragility; it may be triggered by alcohol or estrogens (e.g. OCPs)
What is the likely diagnosis in an adult patient that presents with a pruritic rash for 6 weeks (pictured below)?
Tinea corporis (ringworm)
presents as ring-shaped scaly patches with central clearing
What is the likely diagnosis in an elderly patient with a history of significant sun exposure that presents with a rough/flaky lesion? It does not itch or bleed.
Actinic keratosis
has a small chance of progression to squamous cell carcinoma; may be treated with fluorouracil cream
What is the likely diagnosis in an elderly patient with multiple ecchymoses on the hands and forearms? The lesions are not itchy nor painful and laboratory studies are within normal limits.
Senile purpura
due to age-related loss of elastic fibers in perivascular connective tissue
What is the likely diagnosis in an older patient with a black, raised nodule (pictured below)? It has a rubbery texture and oily surface. It has not changed in appearance over time.
Seborrheic keratosis
benign epidermal tumor that often presents with a “stuck on” appearance
What is the most common form of porphyria?
Porphyria cutanea tarda
What is the most common skin malignancy in immunocompromised patients and patients with a chronic scar?
Squamous cell carcinoma
What is the next step in management for a patient that presents with basal cell carcinoma on the cheek (pictured below)?
Mohs surgery
used for high-risk lesions in delicate or cosmetically sensitive areas
What is the next step in management for a patient with a new mole suspicious for melanoma?
Excisional biopsy (with initial margins of 1-3 mm)
features concerning for melanoma include the ABCDE characteristics, symptomatic moles (e.g. itching/bleeding), and moles that look substantially different than the others (“ugly duckling sign”)
What is the next step in management for a teenage male that presents with moderate inflammatory acne refractory to topical retinoids and benzoyl peroxide?
Topical antibiotics (e.g. erythromycin, clindamycin)
oral antibiotics and isotretinoin are reserved for severe or recalcitrant acne
What is the recommended treatment for a patient that develops pruritus and multiple urticaria after taking amoxicillin for a sore throat? The lungs are clear to auscultation and there is no stridor.
Antihistamines + discontinuation of amoxicillin
the patient is having a mild drug-induced type 1 hypersensitivity reaction and thus an antihistamine is appropriate
What is the recommended treatment for adults with scabies?
topical permethrin or oral ivermectin
What is the recommended treatment for dermatitis herpetiformis?
dapsone (acute relief) and a gluten-free diet (long-term relief)
What is the recommended treatment for seborrheic dermatitis in adults?
Topical antifungals
pathogenesis may involve Malassezia infection
What is the target of autoimmune antibodies in patients with pemphigus vulgaris?
Desmosomes (desmogleins 1 & 3)
versus the basement membrane (hemidesmosomes) targeted in bullous pemphigoid
What metal most likely caused the contact dermatitis pictured below?
Nickel
due to corrosion of nickel in jewelry upon exposure to sweat; copper causes a greenish discoloration of skin
What patient population is likely to have a prolonged course of molluscum contagiosum, with widespread papules?
Immunocompromised patients (e.g. HIV)
What skin malignancy is most likely in a patient with a significant history of sun exposure and a slow-growing lesion (pictured below)?
Basal cell carcinoma
typically appears as a pearly-pink papule with telangiectat
What underlying condition is associated with acanthosis nigricans in older individuals?
GI malignancy
Which type of skin infection involves the deep dermis and manifests as a flat, erythematous rash with indistinct borders?
Cellulitis
Which type of skin infection involves the superficial dermis and manifests as raised, sharply demarcated edges?
Erysipelas
typically caused by Streptococcus pyogenes
