MKSAP Quiz: generalized, intensely pruritic eruption
MKSAP Quiz: generalized, intensely pruritic eruption
A 65-year-old man is evaluated for a generalized, intensely pruritic eruption that has been slowly progressing over the last 6 months. He has been treated with topical corticosteroids for 4 months for widespread eczema without relief of pruritus or change in clinical appearance. He has never had a skin biopsy. He does not have a personal or family history of asthma, atopic dermatitis, allergic rhinitis, or psoriasis.
On physical examination, temperature is 37.5 °C (99.5 °F), blood pressure is 135/85 mm Hg, pulse rate is 84/min, and respiration rate is 14/min. Skin examination reveals erythema with scale affecting greater than 90% of the body surface area. Alopecia, nail dystrophy, and ectropion (turning inside out of the eyelid) are present. There are thickening and fissuring of the skin on the palms and soles. Bilateral axillary and inguinal lymphadenopathy are present. The mucous membranes are not involved.
Which of the following is the most appropriate next step in management?
A. Antinuclear antibody assay
B. Cyclosporine
C. Phototherapy
D. Rapid plasma reagin test
E. Skin biopsy
MKSAP Answer and Critique
The correct answer is E) Skin biopsy. This item is available to MKSAP 15 subscribers as item 26 in the Dermatology module.
This patient's signs and symptoms are consistent with a slowly evolving erythroderma. An underlying cause for erythroderma should always be sought in order to guide therapy and determine prognosis. The diagnosis of idiopathic erythroderma is one of exclusion and should only be made after all other potential causes have been ruled out. Skin biopsy with routine hematoxylin and eosin staining should be performed in every patient with erythroderma; however, histopathologic findings diagnostic of the underlying cause are present in only 50% of patients. If the initial biopsy is nondiagnostic, additional biopsies may be useful and are recommended. This patient's disease, previously diagnosed as eczema, began in adulthood and has not responded to therapy (topical corticosteroids) that is typically effective in the treatment of atopic dermatitis. In addition, he had no personal or family history of atopy (asthma, atopic dermatitis, allergic rhinitis). Atopic dermatitis rarely presents in adulthood in patients without a personal or family history of atopy and is most commonly confused in this setting with cutaneous T-cell lymphoma. Therefore, the most important next step in the management of this patient is a skin biopsy to rule out cutaneous T-cell lymphoma/Sézary syndrome.
Cyclosporine and phototherapy are potential treatments for erythroderma, either idiopathic or related to a particular cause. However, before treating erythroderma with a systemic agent or phototherapy, the cause of the erythroderma should be sought.
Antinuclear antibody and rapid plasma reagin are tests for autoimmune connective tissue disease and syphilis, respectively. Neither autoimmune connective tissue disease nor syphilis commonly causes erythroderma, making these options incorrect.
Key Point
- A skin biopsy is always required in the evaluation of a patient with erythroderma.