Immediate hypersensitivity: a clinical review.

Diseases in which immediate hypersensitivity (IH) reactions occur, (asthma, allergic rhinitis and eczema) are very common in Australia although their overall prevalence is unknown. Until recently the clinical investigation of IH has been undertaken almost exclusively by allergists using scratch tests. The discovery of Ige by Ishizaka et al. in 1966 resulted in a rapid increase in the understanding of the processes involved in IH reactions and, although much remains unclear, respiratory physicians,immunologists and epidemiologists are becoming increasingly involved in investigating the IH reactivity of individuals and populations. In this review the immunological basis of IH reactions is briefly presented; the role of skin tests in their assessment is evaluated and the relationship between IH and clinical allergic disease is discussed in terms of patient management.