Pemphigus-like lesions induced by imiquimod

Area of Science:

• Dermatology
• Immunology
• Oncology

Background:

• Imiquimod is an immunomodulator approved for superficial basal cell carcinomas (sBCC).
• While local adverse events are common, systemic adverse events are also documented.
• Understanding the full spectrum of imiquimod's side effects is crucial for patient safety.

Observation:

• A 60-year-old woman developed pemphigus-like lesions after applying imiquimod cream for sBCC.
• Lesions appeared both at and distant from the application sites.
• Histopathology revealed intraepidermal acantholytic blistering, with negative direct immunofluorescence.

Findings:

• The patient's lesions resolved upon discontinuation of imiquimod.
• This is the first reported case of imiquimod-induced pemphigus with lesions distant from the application site.
• Previous cases of imiquimod-induced pemphigus have been documented.

Implications:

• Systemic absorption of imiquimod or increased cytokine synthesis may explain the distant lesions.
• Lower doses of imiquimod may be advisable for treating extensive or multiple sBCCs.
• This case underscores the importance of monitoring for systemic adverse events during topical imiquimod therapy.