Delayed-type hypersensitivity skin testing. A review.

Delayed hypersensitivity skin testing is based on the reaction that occurs in response to the intradermal injection of an antigen. The technique, interpretation, and pitfalls of interpretation of delayed hypersensitivity skin testing are presented. The histologic findings and immunologic mechanisms characterizing this form of immunologic response are discussed. The diagnostic and clinical importance of reactivity to recall skin test batteries, common microbial antigens, dinitrochlorobenzene, and tumor-associated antigens is also discussed.