Background: Allergy belongs to the most frequent chronic diseases in developed countries. Its manifestation and development are determined by genetic predisposition as well as specific and non-specific environmental factors. The aim of this paper was to evaluate the type and incidence of allergic/atopic diseases among family members (1st and 2nd degree of kinship) of children with the diagnosis of hypersensitivity to cow's milk.
Material/Methods: Positive family history of atopic and allergic diseases among the closest relatives was analysed in a group of 180 children with the diagnosis of hypersensitivity to cow's milk.
Results: Allergoses were found in 163 (91.1%) families, affecting 55.5%, 36% and 50% mothers, fathers and siblings of the patients, respectively. The disease of the same type as in children was present in 37.2% siblings and in 11.7% parents. Forty-five per cent of patients were from high-risk families, where 2, 3 or 4 relatives were affected by the disease (in 37.8%, 6.7% and 0.56% cases, respectively).
Conclusions: Clinical manifestation of allergoses differed between various generations of the same family. The systems most often affected by the allergic process were skin, gastrointestinal tract and respiratory system.

Keywords: food allergy, positive family history of allergy