Search

Abstract: Immediate-reading skin tests (pricks and intradermal tests) are indicated in patients reporting symtoms suggesting immediate-type hypersensitivity reactions. The diagnostic and/or predictive value of these tests is good with betalactams, latex and myorelaxants, and several other substances such as corticosteroids, dyes, antiseptics, vaccines, etc. Non irritant concentrations have been determined for several substances (betalactams, myorelaxants, etc.), but are unknown for numerous other substances. For other substances, non irritant concentrations in skin tests should be evaluated in control patients, in parralel with skin tests performed in patients. The diagnostic value of nonimmediate-reading skin tests is highly variable, and depends on the drug and the nature of the symptoms. Although the sensitivity and the specificity of nonimmediate-reading skin tests are not perfect, these tests are useful in the diagnosis of mild to moderately severe toxidermias, such as nonimmediate urticarias and angio-oedemas, fixed drug eruptions, maculopapular rashes, and acute generalized exanthematic pustulosis. In contrast, their diagnostic value is low in potentially severe toxidermias. The diagnostic value of responses in intradermal tests is usually higher than in patch-tests. However, patch-tests may be positive in few patients with negative intradermal tests. Ideally, skin tests should be performed between 6 weeks and 1 to 2 years after the clinical reaction. However, most nonimmediate drug sensitizations can be diagnosed several years later. [Copyright &y& Elsevier]