Clues to an accurate diagnosis of contact dermatitis.

An accurate diagnosis of allergic contact dermatitis can be achieved by a combination of historical, morphologic, and diagnostic steps. Clues in the history and physical examination can point to an irritant as the source of contact dermatitis. While irritants and allergens share many common features both immunologically and clinically, there are grounds for the distinction. Knowledge of occupational factors is necessary to assess the source of contact dermatitis. A common pitfall is the failure to appreciate the role of endogenous factors in the clinical presentation and overall care of the dermatitis patient. A comprehensive assessment of the patient's environment will lead to appropriate patch tests being applied and a correct diagnosis being reached.