A 62-year-old man with an insignificant past medical history presents with anxiety about several “skin bumps.” He has a family history of melanoma and endorses spending much time in the sun as a child. Physical examination is unremarkable except for the lesion seen in the figure below (Figure below).
Which of the following represents the most appropriate next step in management?
Reassurance. The patient in this question is presenting with skin lesions that have a “stuck on” appearance with an overlying rough and scaly surface. This is a classic example of the common dermatologic condition known as seborrheic keratosis. Seborrheic keratoses are benign skin growths that require no treatment. (A, C) If there is doubt about the less common likelihood of nodular melanoma, a biopsy should be performed. Of note, the sudden appearance of many seborrheic keratoses can be a sign of a gastrointestinal malignancy.
A 22-year-old man with a history of asthma presents with a 2-day history of several small and scaling erythematous papules and plaques on his torso, back, and all four extremities. The patient reports that 3 weeks ago he had an unrelenting sore throat that just recently resolved. The patient has never had this skin condition before and denies a family history of psoriasis or any other dermatologic condition.
Which of the following is the likely diagnosis?
: Guttate psoriasis. The patient's clinical presentation in this question is consistent with a diagnosis of guttate psoriasis. Guttate psoriasis is the second most common form of psoriasis and accounts for less than 10% of cases. Dermatologic examination reveals numerous small and scaling erythematous papules and plaques on the torso and extremities. This type of psoriasis often follows streptococcal pharyngeal infection, so patients should be asked about a recent sore throat or diagnosis of streptococcal pharyngitis. (A) Plaque-like psoriasis is the most common form of psoriasis (nearly 90%) and is characterized by sharply demarcated erythematous scaling plaques, commonly on the elbows, knees, and scalp. (B, D) Pustular and erythrodermic psoriasis are the most severe forms of psoriasis as they both can compromise the protective functions of the skin (temperature control, fluid maintenance, electrolyte balance). Pustular psoriasis is associated with pus-filled blisters rather than plaques. Erythrodermic psoriasis, unlike the other types of psoriasis, usually affects the entire body and gives the skin a “burned” appearance.
A 32-year-old woman presents with pruritic skin lesions on the upper back. The patient reports that the number of skin lesions has increased over the last 2 years. Physical examination reveals several hypopigmented macules of varying sizes affecting the upper back. Dermoscopy reveals fine scale over the majority of the lesions. A potassium hydroxide examination is performed (Figure below).
Which of the following is the correct treatment for this condition?
Topical selenium sulfide. The patient in this question likely has pityriasis (tinea) versicolor, a superficial fungal infection with Malassezia species. The skin lesions in pityriasis versicolor are hypopigmented or hyperpigmented macules of varying sizes, often affecting the upper trunk, arms, chest, shoulders, and face. The skin lesions in this condition are often irregular, well-demarcated, covered by a fine scale, and mildly pruritic. Given the interference with melanin production, pityriasis versicolor often results in hypopigmented lesions, but in light-skinned people, lesions can be pink or light brown. A potassium hydroxide examination is diagnostic and reveals a “spaghetti and meatballs” appearance (rod-shaped hyphae intermixed with spores). Treatment is with topical selenium sulfide or topical ketoconazole. (A) Topical corticosteroids would treat the symptomatic itching, but not the underlying fungal infection. (B) Terbinafine would indeed treat pityriasis versicolor, but is too strong of a medication (associated hepatotoxicity) to use as first-line therapy. This would be an appropriate agent if the patient does not respond to topical treatment. (D) Reassurance should not be offered as a treatment option due to the pruritus affecting an individual's quality of life.
A 42-year-old man presents with a chronic and severely pruritic rash on his bilateral elbows and buttocks. The patient first noticed the rash 9 months ago and reports that the itching has worsened over the last 3 months. Review of systems is unremarkable except for some loose stools over the past 3 years. Physical examination reveals grouped papulovesicular lesions on the extensor regions of his bilateral elbows and buttocks (Figure below).
Which of the following diseases is associated with this chronic blistering skin condition?
Celiac disease. The patient in this question likely has dermatitis herpetiformis, a chronic blistering skin condition characterized by intensely pruritic papulovesicular skin lesions located symmetrically on extensor surfaces. Although the mechanism is not fully known, dermatitis herpetiformis is associated with gluten intolerance and celiac disease. Diagnosis is confirmed by ordering anti-endomysial antibodies of the IgA type and a skin biopsy (immunofluorescent studies demonstrate IgA in the dermal papillae). Treatment is with a gluten-free diet and dapsone (mechanism of efficacy is not entirely understood). (A, C) Crohn disease and ulcerative colitis both can present with extraintestinal manifestations, but not dermatitis herpetiformis. Rather, ulcerative colitis and Crohn disease are associated with pyoderma gangrenosum (deep necrotic ulcers typically located in the lower extremities). (D) Although the name dermatitis herpetiformis seems to suggest a relationship with the herpes virus, the name is simply based on the skin lesions looking similar to herpetic lesions (grouped vesicles).
A 57-year-old man presents with a blistering rash on his chest and upper arm (Figure below). He reports that the blisters often erupt and are mildly pruritic. He denies oral lesions. Nikolsky sign is negative. Biopsy is performed which reveals linear immunofluorescence of the epidermal basement membrane.
Which of the following is the underlying mechanism of this disease?
IgG antibodies against hemidesmosomes. The patient in this question is presenting with signs and symptoms consistent with bullous pemphigoid. Given that Nikolsky sign (separation of the epidermis with lateral stroking of the skin) is negative and the biopsy demonstrated linear immunofluorescence of the epidermal basement membrane, bullous pemphigoid is more likely than pemphigus vulgaris. The underlying mechanism of this autoimmune disease involves IgG antibodies against hemidesmosomes (located on the epidermal basement membrane). Bullous pemphigoid often spares the oral mucosa and presents with tense blisters. (A) IgG antibodies against desmosomes is the mechanism underlying pemphigus vulgaris (PV), which has a higher mortality. Immunofluorescence studies in PV reveal antibodies around keratinocytes in a netlike pattern (intraepidermal separation rather than subepidermal separation associated with bullous pemphigoid). Furthermore, blisters tend to be flaccid in PV and Nikolsky sign is positive. (B) IgA deposition in the dermal papillae is the mechanism underlying dermatitis herpetiformis, which is associated with celiac disease. (C) A Type IV hypersensitivity reaction following exposure to an allergen is consistent with allergic contact dermatitis.
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