Atopy in children with and without a family history of atopy. II. Skin reactivity.

The influence of prolongation of breast feeding and postponement of introduction of solid food during infancy on skin reactivity at the age of five years was studied. At least one positive skin prick test result was observed in 23% of the 70 children with a family history of atopy and in 17% of the 58 children with no such history. Of the 26 skin-test-positive children, 54% exhibited positive reactions to cat dander and 42% to birch pollen. Of the 6 children with asthma, 6 with rhinitis and 17 with eczema, skin reactivity was observed in 66%, 66% and 35%, respectively. Contact with a cat during the first three to four months of life did not correlate with skin test positivity at the age of five years. Skin test positivity to birch pollen was more common in children born in January to February, probably because they were at a vulnerable age in their first birch pollen season in May. No preventive effect by the diet consumed during infancy was seen on subsequent skin test results in relation to common allergens.