Can early exposure to farm animals reduce atopic dermatitis risk?

The treatment of atopic dermatitis has changed over the years and as the treatments have changed, so has the understanding of the disease and what could potentially modify the incidence of the condition. One of the potential modifiers has been exposure to animals, specifically farm animals. An investigation in the Journal of Allergy and Clinical Immunology offered some much needed evidence.¹

Researchers used the Wisconsin Infant Study Cohort to find the environmental exposures, health history, and clinical outcomes of farm families and non-farm families. Being a farm family was defined as living on or within 1/8th mile of a farm; working on a farm; and having regular exposure (≥4 days per week) with cattle, goats, or pigs. Exposure from the prenatal and early postnatal visits were examined along with a report from parents of a diagnosis of atopic dermatitis from a health care provider through age 24 months.

A total of 104 farm families and 122 nonfarm families were included in the analysis. The researchers found that children who came from farm families had a reduced incidence of atopic dermatitis (P = .03). The researchers found that prenatal and early postnatal exposures to specific animals had an inverse link to atopic dermatitis including poultry (3% vs 28%; P = .003), pig (4% vs 25%; P = .04), and feed grain (13% vs 34%; P = .02). Additionally, the researchers found that children who lived on farms with a variety of livestock and had a lot of time spent with indoor and outdoor dogs had a reduced incidence of atopic dermatitis whereas children who lived on farms but had the lowest amount of exposure to animals had an incidence of atopic dermatitis that was similar to children who did not live on farms.

The researchers concluded that living on a farm as an infant can reduce the incidence of atopic dermatitis. Further, exposure to a variety of animals as well as feed when in utero and in early life can also reduce the risk of early-onset atopic dermatitis.

Reference

1. Steiman C, Evans M, Lee K et al. Patterns of farm exposure are associated with reduced incidence of atopic dermatitis in early life. Journal of Allergy and Clinical Immunology. 2020;146(6):1379-1386.e6. doi:10.1016/j.jaci.2020.06.025