CASE REPORT
An African American male in his 80s with a past medical history of atrial fibrillation, congestive heart failure, type 2 diabetes mellitus, hypertension, prostate cancer, chronic kidney disease, and a previous cerebrovascular accident presented with complaints of a pruritic rash on his neck, chest, abdomen, arms, and groin for two weeks. He was given topical clotrimazole-betamethasone ointment by his primary care provider which was ineffective. Skin examination was significant for erythematous to brown scaly plaques arranged in a vertical linear and reticulated distribution throughout his entire chest, back, abdomen, flanks, groin, and proximal thighs (Figures 1-3).
Additionally, there were a few pink oval plaques scattered on his forearms and a hyperpigmented patch on the right neck. An initial punch biopsy of the right shoulder yielded findings of subacute spongiotic and psoriasiform dermatitis with areas of confluent parakeratosis and eosinophils. The exam and biopsy were consistent with contact dermatitis or a drug-induced psoriasiform eruption. The patient was started on topical triamcinolone ointment and an oral prednisone taper. The patient's pruritus improved on the oral steroids; however, taper had to be stopped after 2 days due to a severe increase in his blood glucose levels. He was re-evaluated in dermatology clinic and a second punch biopsy was sent for direct immunofluorescence (DIF). At that time, he was started on dupilumab injections given recurrent pruritus, as well as clobetasol ointment. Immunofluorescence studies demonstrated IgG and IgA deposition on the epidermal side and C3 deposition on the dermal side, consistent with BP. The patient experienced significant improvement in pruritus and skin appearance and agreed to continue the dupilumab
