P029 A case of atypical bullous pemphigoid

Abstract

We present a case of atypical bullous pemphigoid in a young man potentially triggered by occupational chemical exposure. A 31-year-old Lithuanian man presented with a 1-month history of a pruritic, erythematous rash on the arms that spread to the trunk and distal extremities, with peeling palmoplantar keratoderma. The rash was unresponsive to Zerobase cream, clobetasone 0.05% cream, Dermol 500 lotion and flucloxacillin. Within 4 weeks, he became suberythrodermic. There was a clear demarcation at the neckline sparing the head and neck area. On his upper and lower limbs, there were vesicles and bullae at various stages, some of which were deroofed leaking serous fluid. There were linear blisters along the excoriation lines on his limbs. The nails, hair and mucous membranes were normal. He had no significant past medical history, regular medications or allergies. He had restarted this job as a pig farm cleaner 3 months prior to onset of the rash. He was exposed to a range of Mido Foam products over Airflex personal protective equipment and a face shield. The differential diagnoses include contact dermatitis, atypical bullous pemphigoid and lichen planus pemphigoides. Serum skin autoantibodies were negative. An incisional biopsy taken from his left thigh revealed subepidermal bullae with mixed inflammatory cells including eosinophils and occasional Civatte bodies. Direct ­immunofluorescence of perilesional skin showed strong linear C3 staining at the basement membrane zone. Salt-split skin showed linear deposition of IgG and C3 to the roof of the dermoepidermal junction. These findings were consistent with bullous pemphigoid. Negative skin autoantibodies in a young patient with Koebner phenomenon, a higher blister density on the extremities, and well-demarcated linear erythema at the neck raise the possibilities of lichen planus pemphigoides or chemical-induced bullous pemphigoid. The patient responded well to clobetasol propionate ointment and prednisolone 40 mg weaned over 8 weeks, before transitioning onto mycophenolate mofetil.