For patients with bullous pemphigoid (BP), new or worsening blisters and redness are often seen as a sign of disease relapse or treatment failure. However, a case report from Southern Medical University highlights an alternative explanation: crusted scabies (CS) masquerading as uncontrolled BP.

The patient, a 66yearold man with hypertension and diabetes, had been on longterm systemic corticosteroids for BP, with dupilumab later added as a steroidsparing agent. After his sixth dupilumab injection, severe generalized pruritus and worsening erythematous and vesiculobullous lesions developed. At presentation, he was receiving prednisone 30 mg/day but remained poorly controlled. Examination showed confluent dusky erythematous patches with thick hyperkeratotic scaling and crusts on the trunk and lower extremities, and scaling in the interdigital spaces. Microscopy of skin scrapings confirmed Sarcoptes scabiei eggs and mites. Biopsy and direct immunofluorescence confirmed active BP. Peripheral eosinophilia was also noted.

Because oral ivermectin was unavailable, the patient received oral tinidazole 1 g daily for one week plus topical 10% sulfur ointment. Dupilumab was stopped, but prednisone was maintained at the same dose. Within one week, pruritus completely resolved, crusting markedly regressed, and no new bullae appeared.

The authors note that CS may present atypically in immunosuppressed individuals, with diffuse scaling and crusting while classic burrows are absent. In BP patients, such findings can be misinterpreted as relapse or resistance. They emphasize that persistent pruritus, crusting, or interdigital scaling should prompt evaluation for scabies, and prompt mite eradication should be prioritized.

The work titled “Crusted Scabies Complicating Bullous Pemphigoid” was published on Skin (published on August 10, 2026).
DOI：10.2738/SKIN.2026.0013