A man presents with a crusted folliculitis that has failed to respond to antibiotics. What are these lesions and how can they be treated?
A 45-year-old man developed multiple, nontender, violaceous and focally crusted follicular lesions on his left shin. Despite multiple courses of antibiotics, which he received over a 12-month period, fresh lesions developed and older lesions resulted in areas of hair loss and mottled pigmentation (Figure 1). A deep skin biopsy showed a marked mixed inflammatory reaction with a granulomatous component in the deep dermis surrounding a loose hair shaft in the subcutis (Figure 2). Closer examination of the hair shaft revealed rows of spores (Figure 3).