An allergic reaction that becomes apparent in a sensitized person only minutes after contact WordNet 3.0 & Open English WordNet

Atopy is the tendency to produce an exaggerated immunoglobulin E immune response to otherwise harmless substances in the environment. Wikipedia

Predisposition towards allergy Wikidata

A hereditary disorder marked by the tendency to develop localized immediate hypersensitivity reactions to allergens such as pollen, food etc and is manifested by hay fever, asthma, or similar allergic conditions; generally considered to be caused by the interaction of environmental and genetic factors. Wiktionary

Hereditary disorder. Wiktionary (translation)