RAST: Clinical applications

Allergic diseases are multifactorial, heterogeneous disorders caused by the interaction of environmental and genetic factors. Over 25% of the world's population suffer from allergic diseases including asthma, allergic rhinitis, eczema, and drug reactions. In recent years, the prevalence of allergic diseases has increased annually throughout the world seriously affecting the quality of life of the patients, and creating a serious burden on both health and society. Such conditions constitute a challenge for both public health organizations and healthcare providers. The pathogenesis of allergic diseases has generally been considered to be driven by immunity, including IgE overproduction, IgE receptor abnormality, and Th2-skewed Th cell differentiation. The present review aims to critically analyze the potential and the applicability of the radioallergosorbent test (RAST) in the diagnostic process of allergic skin diseases. This is a very intricate and complex process which should has to be founded on patients' medical history. However, the patient and family's own perceptions and knowledge may influence history so laboratory studies represent a very informative tool in the diagnosis of allergic skin diseases. In particular, in vivo methods, such as prick test, often represent the first choice because they are not expensive, immediate and not invasive. Therefore, alternative in vitro methods like RAST are preferred in particular conditions, including severe eczema or when there is persistent dermatographism.