Recurrent Vesicles, Papules, and Plaques in a Teenager—Quiz Case

A 16-year-old African American boy presented to the emergency department with a 2-week history of an enlarging focus of erythema and induration over his right elbow. His symptoms reportedly began with the localized onset of pruritic papules that coalesced to form a large plaque. After 1 week, the region had become markedly indurated, with weeping of serous fluids, and the patient was seen by a local physician, who prescribed cephalexin. Despite the antibiotic therapy, the inflammation and induration continued to worsen.

At the time of presentation, the patient denied fever, chills, nausea, or fatigue. His medical history was significant for 2 prior episodes of presumed cellulitis involving the posterior aspect of the right upper extremity and the back of the neck that had occurred within the past 2 years. He reported that these episodes had resolved with oral antibiotic therapy. A clinical diagnosis of cellulitis of the right arm was made, and the patient was admitted to the hospital for treatment.

In the hospital, the patient remained afebrile and without systemic complaints. However, despite broad-spectrum intravenous antibiotic therapy, his condition continued to worsen over the next several days, and his right arm became severely painful and indurated. Also, an annular, erythematous, vesiculopapular eruption developed on the dorsal surface of the left elbow (Figure 1). The patient noted that the eruption resembled the primary lesion that had developed on his right elbow some weeks earlier.

Physical examination revealed a well-demarcated, erythematous plaque with induration, multiple erosions, and serous weeping on the extensor surface of the right elbow and forearm (Figure 2). Edema was present fromthe midhumerus distally to the midforearm. There was no evidence of lymphadenopathy or hepatosplenomegaly. The blood chemistry profile revealed no abnormalities. No bacterial growth was detected in blood or wound cultures. A complete blood cell count showed a white blood cell count of 9700/µL (reference range, 3200-9800/µL), 56% of which were segmented neutrophils (reference range, 37%-80%), 26% were lymphocytes (reference range, 10%-50%), 2% were monocytes (reference range, 0%-12%), and 16% were eosinophils (reference range, 0%-7%). A punch biopsy specimen was obtained from the right forearm (Figure 3 and Figure 4).

Article