Bilateral scaly plaques in axillae: pityriasis rosea of Vidal

A 32-year-old man was referred for acute onset of pruritic scaly eruptions in the axillae of 8 days' duration, which was unresponsive to topical clotrimazole. The lesions consisted of multiple, coalescent oval plaques of 1 cm to 6 cm in longest diameter (Figure 1 and Figure 2) with central clearing and typical collarette scales at the periphery (Figure 3). Other skin areas and mucosal surfaces were unaffected. His general and systemic examinations were normal. Family and past histories were unremarkable except for a "ring worm-like patch" on his lower aspect of the abdomen 4 months ago, which rapidly regressed. On further inquiry, he gave a history of an episode of fever, coryza, and headache 3 weeks earlier to his eruption on the abdomen, which resolved with conservative remedies and one paracetamol tablet. He remained asymptomatic until axillary lesions appeared. We made a provisional diagnosis of pityriasis rosea (PR). Investigations including scrapings for potassium hydroxide examination, complete blood cell counts, urinalysis, blood sugar, VDRL test, and human immunodeficiency virus antibodies were all normal or non-reactive. As cutaneous biopsy revealed parakeratosis, epidermal spongiosis, dermal inflammatory cells, and extravasated red blood cells (Figure 4). The eruptions cleared within 8 days, following treatment with mometasone furoate cream and oral desloratidine 5 mg/d, leaving post-inflammatory hyperpigmentation. There was no recurrence for the next 6 months of observation. He was later lost to follow-up.