Allergologic diagnosis

There are two phases in allergologic diagnosis of respiratory diseases rela ted to immediate hypersensitivity reactions: establishment of the allergic origin of the symptoms and identification of the causal allergen or allerge ns. In addition to the basic information obtained from history taking and physi cal examination, prick tests provide an easy, rapid, and low cost means of correctly identifying specific allergens. Laboratory tests such as serum as say of specific IgE can be useful when history and prick tests provide conf licting information, in exceptional cases when prick tests cannot be perfor med, or when specific desensitization is indicated. IgE assay is however of little use if prick tests are negative or clinical history poorly suggesti ve. The role of screening for atopy using multiple-allergen prick tests which g ive a global positive or negative result is poorly defined. Screening tests would be interesting if symptoms suggest, among other hypotheses, an aller gic disease, especially if prick test cannot be performed rapidly. Other at opy tests, such as total serum IgE, have little use. Finally, specific provocation tests are rarely needed for routine allergolo gic diagnosis. They may be useful in complex clinical situations or in part icular conditions such as occupational allergy.