Early exposure to a food allergen through broken skin might prompt the development of food allergy, according to new research in Allergy and Asthma Proceedings.

This theory gained further support from a recent study that found increased prevalence of food allergy if a child had skin infection or eczema in the first year of life.

“The association of food allergy with early skin infection and eczema, however, might shed some light on how food allergies develop. Our findings support the hypothesis that food sensitization might start with exposure through the skin. This might have implications for prevention of food allergies,” says lead author Ruchi Gupta, MD, MPH, pediatrician and researcher at Ann & Robert H. Lurie Children’s Hospital of Chicago and Associate Professor of Pediatrics and Medicine at Northwestern University Feinberg School of Medicine.

The study included 1,359 participants, from birth to 21 years old, with and without food allergies including siblings who may or may not have had allergies. The similar genetic makeup of the subjects and controls helped the authors assess the impact of different exposures on food allergy and asthma.

Researchers investigated key hygiene factors in association with food allergy and asthma, including antibiotic use, infection history, number of siblings, pet exposure, and maternal child health factors such as maternal age at birth, caesarian section, breastfeeding and out-of-home child care.

The new study showed that food allergy had less profound associations with hygiene factors – such as pet exposure – than asthma. While it is well established in asthma, the hygiene hypothesis has not been thoroughly investigated in food allergy.

In fact, the number of siblings and child care in a child care center were the only hygiene factors that were associated with decreased food allergy, the study showed.

Support for the study came from Food Allergy Research and Education (FARE), and Dave and Denise Bunning.