This document summarizes contact dermatitis, including:
1) It classifies contact dermatitis into allergic contact dermatitis (ACD), caused by T lymphocytes, and irritant contact dermatitis (ICD), caused by irritants without prior sensitization.
2) ACD and ICD have different pathophysiologies - ACD is a type IV hypersensitivity reaction while ICD is a direct tissue reaction.
3) Common allergens that cause ACD include poison ivy, nickel, fragrances, hair dyes, and topical corticosteroids. Irritants that cause ICD include detergents, solvents, and excessive moisture.