A 25-year-old woman with blonde hair and fair complexion complains of a mole on her upper back. The lesion is 8 mm in diameter, darkly pigmented and asymmetric, with an irregular border (shown below).
Which of the following is the best next step in management?
The lesion has characteristics of melanoma (remember the ABCDs: a symmetry, irregular or ill-defined border, dark black or variegated color, and diameter > 6 mm). A full-thickness excisional biopsy is required for diagnosis and should not be delayed. Shave biopsy of a suspected melanoma makes the assessment of depth of invasion difficult. Diagnosis is urgent; the lesion cannot be observed over time. After the diagnosis of melanoma is made, the tumor must then be staged to determine prognosis and treatment.
A 39-year-old man with a prior history of myocardial infarction complains of yellow bumps on his elbows and buttocks. Yellow-colored cutaneous plaques are noted in those areas. The lesions occur in crops and have a surrounding reddish halo.
Which of the following is the best next step in evaluation of this patient?
The description and location of these lesions are suggestive of eruptive xanthomas. Eruptive xanthomas occur primarily on buttocks or extensor surfaces and are associated with elevated triglycerides. Tophaceous gout can result in deposits of monosodium urate, usually in the skin around joints of the hands and feet. Tophi are usually white and may discharge a chalky material. Skin biopsy is not usually necessary to distinguish these lesions. The cutaneous lesions of sarcoidosis (which would usually show disease on CXR) are reddish-brown waxy papules, usually on the face. Obstructive liver disease can occasionally cause palmar xanthomas, which are seen as yellow plaques along the palmar creases.
Xanthomas can be important cutaneous clues for underlying lipid disorders. Xanthelasmas, yellowish plaques on the inner aspect of the upper eyelids, are nonspecific but are associated with hyperlipidemia 50% of the time. Tendon xanthomas are important clues for familial hypercholesterolemia. Tuberous xanthomas, which often present as plaques or even polypoid nodules over pressure points, usually signify hypercholesterolemia. Eruptive xanthomas, again, are associated with triglyceride levels above 1000 mg/dL. Treatment of the hypertriglyceridemia usually results in resolution of lesions. Biopsy of a xanthoma would show lipid-containing macrophages, but is usually not necessary for diagnosis.
A 25-year-old woman complains of low-grade fever, malaise, and sore throat. After this prodromal phase, a rash of discrete erythematous macules begins on her arms and progresses to form painful hemorrhagic pustules on her arms and hands. She is noted to have pharyngeal erythema.
What is the most likely cause of her rash?
Gonococcal infection is sexually transmitted through mucosal invasion, either oral or genital. Disseminated gonococcal infection commonly causes tenosynovitis, septic arthritis, and hepatitis. Sparse, 1- to 5-mm erythematous macules occur within 24 to 48 hours, usually affecting the arms more than the legs. Cat-scratch disease is associated with a history of cat contact in 90% of cases and presents with tender lymphadenopathy. Bedbug (Cimex lectularius) bites commonly occur in rows of two or three lesions and are pruritic; they do not disseminate. Shingles lesions occur in dermatomal distribution and are vesicular. “Skin popping” is the technique of injecting illicit drugs subcutaneously. This practice can cause localized abscesses, cellulitis, or even tetanus, but would not cause this woman’s pharyngitis or her disseminated discrete pustules.
A 17-year-old adolescent girl noted a 2-cm annular pink, scaly lesion on her back. Over the next 2 weeks she develops several smaller oval pink lesions with a fine collarette of scale. They seem to run in the body folds and mainly involve the trunk, although a few occur on the upper arms and thighs. There is no lymphadenopathy and no oral lesions.
Which of the following is the most likely diagnosis?
The description of this papulosquamous disease is classic for pityriasis rosea. This disease occurs in about 10% of the population, usually in young adults. Pityriasis rosea primarily affects the trunk and proximal extremities. Pityriasis rosea is usually asymptomatic, although some patients have an early, mild viral prodrome (malaise and low-grade fever), and itching may be significant. Drug eruptions, fungal infections, and secondary syphilis may mimic this disease. Fungal infections (tinea) are rarely as widespread and sudden in onset; potassium hydroxide (KOH) preparation will be positive. Psoriasis, with its thick, scaly plaques on extensor surfaces, should not cause confusion. A rare condition called guttate parapsoriasis should be suspected if the rash lasts more than 2 months, since pityriasis rosea usually clears spontaneously in 6 weeks. Lichen planus is a papulosquamous disorder, but it causes intensely pruritic polygonal plaques, often with intraoral involvement. It would not cause a “Christmas tree” pattern on the back as seen in this patient. Secondary syphilis is characterized by lymph-adenopathy, oral patches, and lesions on the palms and soles (a VDRL test will be strongly positive at this stage).
A 45-year-old man with Parkinson disease has macular areas of erythema and scaling behind the ears and on the scalp, eyebrows, glabella, nasolabial folds, and central chest.
Which of the following is true?
The patient has the typical areas of involvement of seborrheic dermatitis. This common dermatitis appears to be worse in many neurological diseases. It is also very common and severe in patients with AIDS. In general, symptoms are worse in the winter. UV radiation improves the condition. Pityrosporum ovale appears to play a role in seborrheic dermatitis and dandruff, and the symptoms improve with the use of certain antifungal preparations (eg, ketoconazole) that decrease this yeast. Mild topical steroids also produce an excellent clinical response. High-dose topical steroids are rarely necessary; when used on the face for long periods of time, they can cause irreversible atrophy and thinning of the skin. Oral fluconazole may be necessary in refractory Candida infections, which usually affect the oral mucosa (thrush), the vaginal mucosa or moist intertriginous areas. Psoriasis (which can cause destructive arthritis) should be easily distinguishable by the pattern of involvement (psoriasis does not prominently affect the face) and by its characteristic thick micaceous scale.
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