The interstitial granulomatous drug reaction (IGDR) is a skin eruption with distinctive clinical and histopathological findings. Lesions are usually localized to skin folds, are asymptomatic, and may not begin until several weeks, months, or even years after drug initiation. Most lesions resolve over weeks following drug cessation. The exact mechanism is unknown.

Calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, lipid-lowering agents, antihistamines (H2 receptor antagonists), furosemide, carbamazepine, anti-tumor necrosis factor (TNF) agents, bupropion and tricyclic antidepressants, and soy have all been implicated.

Related topic: Interstitial granulomatous dermatitis