ABSTRACT
Diagnostic in vivo skin tests are used to detect and define the possible exogenous chemical agent that causes a skin disorder, and hence are critical in their scientific documentation. Such chemical agents often cause skin disorders by hypersensitivity mechanisms, which can thus be diagnosed by a provocative test. The anatomical advantage of studying skin disorders is that the skin is easily accessible for testing. diagnostic procedures include patch, intradermal, prick, scratch, scratch-chamber, open, photo, photopatch, and provocative use tests. The skin disorders in which such tests are useful include drug eruptions, contact dermatitis, and immediate contact reactions, and possibly sensory irritation. Drug eruptions are a heterogeneous class of adverse skin reactions due to ingestion or injection of therapeutic drugs. In cases of nonimmunological drug eruptions, skin tests are usually negative, and systemic provocations are also often negative. Contact dermatitis is commonly divided into irritant contact dermatitis and allergic contact dermatitis.
