A 78-year-old fair-skinned woman presents to her dermatologist with chronic pruritis which, after 2 months, has turned into itchy, hive-like blisters. She has a history of high blood pressure and rheumatoid arthritis and is currently taking a diuretic once daily and an anti-inflammatory twice a day. The patient believed she had eczema and self-treated with topical steroids, which provided no relief. As soon as her blisters clear, new blisters occur accompanied by papules, resembling lesions of lichen planus.
The hive-like blisters appear all over the body, but particularly on her arms, legs, abdomen, groin, armpits, and inner thigh. The dermatologist decides to take a skin biopsy, which shows subepidermal blistering and eosinophil infiltration. Direct immunofluorescence finds IgG along the dermal-epidermal junction.