A 59-year-old woman with a 10-year history of latent autoimmune diabetes in adults (LADA), managed on insulin, presented to the dermatology clinic with a progressive, pruritic rash. Over the course of months, the rash gradually spread to involve her chest, back, flanks, and extremities (Figure 1). Her primary symptom was pruritus. She was without skin pain or mucosal involvement. She had no history of a similar rash. She had previously tried over-the-counter topical corticosteroids without improvement in her symptoms. Interestingly, she reported that her identical twin sister, also diagnosed with LADA, had developed a rash similar in appearance 2 years earlier. Per the patient’s report, her sister’s rash was quite recalcitrant to medical therapy, requiring numerous topical and systemic agents to control it.
On physical exam, pink annular plaques with slightly raised borders admixed with coalescing pink papules diffusely scattered over the flank, extremities, and chest were observed...
