Which drug is described as the most common cause of contact dermatitis?

• A. Acetazolamide
• B. Dorzolamide
• C. Timolol
• D. Latanoprost

Answer: (A)

Drug-induced contact dermatitis is a delayed hypersensitivity reaction to a medication, often linked to the presence of a sulfonamide group in the drug. Acetazolamide, a systemic sulfonamide carbonic anhydrase inhibitor, is a classic sensitizer; its sulfonamide structure makes it more likely to trigger a true allergic contact dermatitis compared with the other options. While dorzolamide is also a sulfonamide and can cause local irritation, the systemic exposure and sensitization associated with acetazolamide make it the more common culprit in this context. Timolol and latanoprost are less typically associated with true contact dermatitis and more with other local or systemic effects.