DRUG PATCH TESTS IN CUTANEOUS ADVERSE DRU G-REACTIONS

Skin patch tests with drugs suspected of being responsible for cutaneo us adverse rug reaction represent an easy method of aetiological inves tigation, but this methodology must be defined in order to determine t he sensitivity and specificity of these tests. A practical methodology for these patch tests is proposed. According to the preliminary evalu ation of this method and the data of the literature, drug patch tests are positive in 30 to 43% of cases of cutaneous adverse drug reactions . Their sensitivity depends on the clinical type and therefore the imm unological mechanism of the cutaneous adverse drug reaction (these tes ts are more sensitive in maculopapular rash than in urticaria) and pro bably the drug responsible. These skin tests have a good specificity, but several drugs can induce false-positive results, which means that the results of patch tests must always be compared with those of thoro ughly selected negative controls, as these tests are potentially sensi tizing.