Drug-Induced Bullous Pemphigoid

Pathophysiological Mechanisms

Bullous pemphigoid is an autoimmune subepidermal blistering disease characterized by autoantibodies targeting components of the adhesion complex in the basement membrane zone, particularly BP180 and BP230 antigens 1
The strongest evidence for drug-induced bullous pemphigoid exists for medications such as gliptins, loop diuretics, particularly furosemide, spironolactone, and neuroleptics 1

The latency between starting the drug and disease onset can range from weeks to several months 2
Some distinguishing features of drug-induced BP may include more frequent pruritus compared to idiopathic pemphigus 2
Potential for complete resolution upon drug withdrawal in some cases 2
Diagnosis requires a detailed medication history, particularly focusing on recently introduced drugs, and standard diagnostic criteria for BP including clinical features, histopathology, and direct immunofluorescence showing linear IgG/C3 deposits along the basement membrane zone 3

The primary management step is identification and discontinuation of the suspected triggering medication 2
After drug withdrawal, approximately 50% of cases may persist, requiring conventional BP treatment 2
For persistent or severe cases, superpotent topical corticosteroids are recommended as first-line therapy, and systemic corticosteroids may be necessary for widespread disease 4

A thorough medication history is essential in all patients presenting with BP, particularly in elderly patients who may be on multiple medications 3
Poor response to standard treatments should raise suspicion for drug-induced BP 2
Regular monitoring for disease activity is important, with follow-up visits recommended every 2 weeks for the first 3 months, then monthly for the next 3 months 4
When managing elderly patients with BP, consider the mortality risk associated with high-dose systemic corticosteroids 5