BG14 Refractory pruritus in older patients: a case of prebullous pemphigoid mimicking folliculitis and generalized eczema

Abstract

Bullous pemphigoid is the most common autoimmune blistering disorder in older adults. It often begins with a prolonged prebullous phase characterized by intense pruritus and nonspecific inflammatory skin changes. This early prebullous phase commonly results in diagnostic delay. In older patients, early recognition is critical, as comorbidities may limit treatment options and increase the risks associated with prolonged systemic corticosteroid use. We describe an 87-year-old man with ischaemic heart disease who presented with a 6-month history of a persistent, intensely pruritic rash that significantly disrupted sleep and quality of life. He had no personal history of eczema. The eruption began on the back and gradually spread to the trunk and limbs. Initial treatment for presumed folliculitis and scabies with doxycycline and permethrin was ineffective. A subsequent course of oral and potent topical corticosteroids resulted in minimal improvement in pruritus. A skin biopsy performed before systemic corticosteroid therapy showed spongiotic dermatitis with prominent eosinophils and mild papillary dermal oedema. Clinical examination revealed widespread eczematous and urticarial plaques without blisters, erosions, mucosal involvement or facial lesions. Given the severity and persistence of the pruritus in combination with eosinophil-rich histology, prebullous pemphigoid was suspected. Indirect immunofluorescence demonstrated IgG antibasement membrane zone antibodies, and enzyme-linked immunosorbent assays were positive for anti-BP180 and anti-BP230 antibodies. Age-appropriate malignancy screening, including tumour markers and imaging, was unremarkable. In view of the patient’s age and cardiovascular comorbidity, methotrexate was commenced, resulting in good disease control. This case highlights the need to consider prebullous pemphigoid in older adults presenting with chronic, treatment-resistant eczematous or urticarial eruptions. Early biopsy and immunological testing can facilitate timely diagnosis and appropriate, comorbidity-­conscious management.