Allergic diathesis - anomaly of the constitution, described predisposition of an organism to allergic diseases. Some authors identify allergic and exudativly catarral diathesises, others consider exudativly catarral diathesis as display of an allergic diathesis.

It is possible to carry changes of immune metabolic tolerance for antigens and biologically active substances to feature of an allergic diathesis. Predisposition to an allergy is clinically shown only at influence of adverse factors of an environment. Among allergic conditions children, especially early age, most often have a food allergy. The medicinal, inhalation, infectious allergy is less often observed.

Clinical displays of an allergy are extremely diverse. At children dermal, gastrointestinal, respiratory displays, and also lesions of nervous and cardiovascular systems, disturbances of a thermoregulation are marked. To the latent markers of an allergic diathesis concern: genetically determined hyperproduction IgE. Their functional activity; constant deficiency secretory IgA; an eosinophilia; instability of an exchange; rising of the relative maintenance of polynonsaturated fat acids, in particular arachidonic, in lipide structures of cellular membranes; dropping of sensitivity (adrenoreceptors; positive assays with not bacteriemic allergens; positive data of the family allergological anamnesis.