Allergic contact dermatitis: clinical aspects.

The best way to be acquainted with the various facets of clinical lesions of allergic contact dermatitis (ACD) is to refer to the concept of the ACD syndrome. Obtaining differential diagnosis between irritant contact dermatitis and ACD based on clinical grounds is difficult. Moreover, hand eczema and photoalleregic contact dermatitis deserve special attention. The patch test remains the "gold standard" diagnostic tool, but many other very useful complementary tests have been developed in recent years.