• Posted March 6, 2026

Peanut Allergy Risk Higher If Older Sibs Eat Peanuts, Study Finds

Young kids have a higher risk of peanut allergy if their older brothers or sisters love to eat peanuts, a new study has found.

However, this risk can be headed off by getting younger siblings to eat peanuts themselves, researchers reported at the annual meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) in Philadelphia.

Children were “at increased risk of peanut sensitization and allergy if the younger sibling did not introduce peanut into their diet in the first year of life and had household members consuming peanut,” lead researcher Dr. Michelle Huffaker, an allergist and immunologist at Stanford University, said in a news release.

For the new study, researchers followed up on the younger siblings of children who’d participated in an earlier clinical trial called Learning Early About Peanut allergy (LEAP).

The research team assessed the household peanut exposure of the children, based on what they’d learned from their older siblings.

Results showed that the children were 16 times more likely to become sensitive to peanuts and 13 times more likely to develop peanut allergy if their families – and especially their older siblings – ate more peanuts and peanut products.

“This risk was even greater for the younger siblings with eczema,” particularly if they’d had eczema for longer, Huffaker said.

Researchers said the results fall in line with a hypothesis that proposes children become sensitized and allergic to some foods just by having them around the house, but not eating them.

However, this risk is significantly mitigated if a toddler is introduced to peanut during their first year of life, results showed.

“These findings support the concept that peanut allergy can develop with exposure to peanut through the skin, and that this risk can be overcome by introducing peanut into the diet at an early age,” Huffaker said.

Researchers presented their findings Sunday at the AAAAI meeting.

Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.

More information

The American Academy of Allergy, Asthma & Immunology has more on peanut allergy.

SOURCE: American Academy of Allergy, Asthma & Immunology, news release, Feb. 10, 2026