CASE
A 45-year-old woman presented for evaluation of a rash that was more or less unchanged for the past 8 to 10 years. The rash was asymptomatic for the most part, except for occasional “spells” during which the surface of the rash became a bit scaly and the rash became mildly pruritic. It had persisted despite a number of treatments, including topical and oral antifungals and the application of numerous topical corticosteroid creams. In all that time, she had never been examined by a dermatology clinician and had never had a biopsy.
The patient denied having any other skin problems but stated that she had other health issues. Rheumatoid arthritis, lupus, and fibromyalgia had been diagnosed in our patient. She was taking hydroxychloroquine (Plaquenil) and various OTC NSAIDs for these conditions.
When asked in particular about the skin problem on her back, she admitted to using a large heating pad turned up “as high as it will go” for her back pain. On some days, she used the pad all day, and she left it on her back most nights.
Examination revealed an impressively large, reticular (netlike) macular pattern of hyperpigmentation that covered most of the patient's back (Figure 1). It was nonblanchable, and a bit of scaling was better felt than seen in a few focal areas. Potassium hydroxide test (KOH prep) was negative for fungal elements.
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