Earlier-Onset Atopic Dermatitis Linked With Cow’s Milk Sensitization: Study

Egg and cow’s milk were the most common food allergens identified by skin prick testing among infants with atopic dermatitis (AD) in a 17-year retrospective study from Iran, although the investigators cautioned that testing alone cannot establish clinically confirmed food allergy.

Published in Immunity, Inflammation and Disease, the case series included 98 infants aged 6 to 24 months with AD evaluated at an asthma and allergy clinic in Kashan, Iran, from 2005 through 2021. Investigators reviewed medical records and skin prick test results for 8 food allergens. Most infants had mild AD (66.3%), while 24.5% had moderate and 9.2% had severe disease.

Egg and Cow’s Milk Sensitization Predominated in Infants With AD

Egg produced the highest rate of positive skin prick tests at 64.3%, followed by cow’s milk at 49.0%, nuts at 35.7%, soy at 20.4%, and wheat at 12.2%. Egg sensitization was significantly more frequent among girls than boys (74.1% vs 52.3%; P = 0.025). Cow’s milk sensitization was more frequent among infants whose clinical manifestations began before 6 months compared with those with later onset (56.1% vs 34.3%; P = 0.044).

Earlier AD onset also differed by disease severity. Infants with severe AD developed clinical manifestations at a mean age of 2.78 months, compared with 5.60 months for mild AD and 7.17 months for moderate AD (P = 0.014). Feeding type during the first 6 months was not significantly associated with food sensitization or AD severity.

The authors noted several limitations, including the retrospective, single-center design, small sample, missing medical-record data, and reliance on skin prick testing without serum-specific IgE testing or oral food challenges. They acknowledged that positive skin prick tests primarily indicate IgE-mediated sensitization and may therefore overestimate clinically confirmed food allergy.

"Allergic diseases and food sensitivities are increasing worldwide," the authors wrote in the conclusion. "Among AD patients, sensitivity to food allergens such as eggs, cow's milk, and wheat is common. Considering the onset of food sensitivity in many patients before 6 months of age, it is recommended that allergenic substances such as egg yolk and wheat should not be used for feeding infants before 6 months of age."

Source

Madani S, et al. Immunity, Inflammation and Disease. 2026. Doi:10.1002/iid3.70544