Early eczema onset increases risk for food allergies in children, researchers find

Key takeaways:

• Eczema onset before age 4 months was associated with a higher number of food allergies vs. onset after 12 months.
• Any eczema in infants — even mild cases — should be treated promptly, an expert said.

WASHINGTON — Early onset of eczema was associated with a greater number of food allergies in children, and the condition also increased the risk for asthma, according to research presented here.

“We know that one of the most important predisposing factors for food allergy is eczema, but what we don't know are the risk factors that make one child with eczema more prone to food allergy vs. the other, because not every child with eczema develops food allergy,” Mahboobeh Mahdavinia, MD, PhD, an associate professor in the department of internal medicine at Rush University, told Healio.

In the study, the researchers analyzed intake surveys from the FORWARD longitudinal, multicenter study, which enrolled white, Black and Hispanic and Latino children aged 0 to 12 years with physician-diagnosed food allergy.

Among 1,107 children in the analysis, 64% reported a lifetime history of eczema.

Mahdavinia and colleagues found that most children reported developing eczema in the first year of life, with:

• 24.9% developing it between 1 to 3 months;
• 27.7% developing it between 4 to 6 months;
• 13.7% developing it between 7 to 12 months; and
• 15.5% developing it after 12 months.

Meanwhile, eczema rates were:

• 41.8% among Hispanic and Latino children;
• 60.3% among Black children; and
• 70% among white children.

Results showed that eczema onset before 4 months was associated with a higher number of food allergies (OR = 1.14, 95% CI, 1.02-1.28) compared with eczema onset after 12 months.

Eczema was also associated with increased odds of:

• asthma (OR = 7.01; 95% CI, 4.99-10.06); and
• allergic rhinitis (OR = 9.42; 95% CI, 6.85-13.17).

Mahdavinia said there was a biological explanation for the association between food allergy and eczema, describing skin as “a barrier” that normally will not allow allergens to pass.

“In children with eczema, unfortunately, the barriers disrupt,” she said. “Allergens that come in contact with the skin will go through [it] and be picked up by the immune cells, called dendritic cells, and that's not the right way for the body to see a food allergen for the first time. The right way is through oral consumption of the food.”

Mahdavinia explained that introducing allergens through the skin “creates a cascade of events that can end in development of food allergy.” “Any — even slight — eczema that's detected in babies needs to be treated appropriately, and that's often with good use of emollience.”

She said most eczema in infancy can be treated effectively with daily moisturizer and emollients, “but more attention should be actually paid to mild, dry skin eczema that a lot of times is not even reported. If [physicians] detect eczema, jump on it and treat it appropriately — it could help in preventing food allergies.”