A 58-Year-Old Man With a Macerated Rash of the Neck and Axilla

A 58-year-old overweight African American man presented with a 5-year history of a slightly pruritic and painful rash of the right lateral area of the neck and right axilla. It was worse during the summers, and blisters sometimes developed. Emollients were unhelpful. The patient was otherwise healthy. His sister had diabetes mellitus and a similar rash in her axillae. The patient performed indoor manual labor as a maintenance engineer and had no significant sun exposure. Physical examination revealed irregularly thickened skin of the right axilla (Figure 1, left) and right lateral area of the neck (Figure 1, right) containing hyperpigmentation, hypopigmentation, multiple acrochordons (skin tags), malodorous crust, and areas of maceration and erosion. Further examination of the skin revealed pseudofolliculitis barbae in the submental and mandibular regions bilaterally. The nails, oral cavity, and mucosal membranes appeared normal. A biopsy of right axillary skin was performed (Figure 2).