Patch testing in adverse drug reactions

Abstract

Cutaneous adverse drug reactions (CADRs), defined as skin eruptions induced by drugs used in adequate doses and in the correct indications, present under different clinical patterns, and the pathogenic mechanisms underlying the reaction are very different. Some are due to immune reactions, particularly dependent on T cells, namely, maculopapular exanthema, drug hypersensitivity syndrome/DRESS, acute generalized exanthematous pustulosis, Stevens-Johnson syndrome, toxic epidermal necrolysis, and fixed drug eruption. These, which bear some similarities with allergic contact dermatitis, can be studied by patch testing performed according to the guidelines presented. Positive results depend mainly on the drug involved and on the type of reaction. They can be of help in confirming a clinically plausible history of a drug eruption and in studying cross-reactions. On the other hand, a negative test does not exclude the involvement of a drug in a cutaneous reaction. © 2011 Springer-Verlag Berlin Heidelberg.