Some babies may need allergy tests before trying peanuts

A vendor sells peanuts at the Voi market (Copyright Reuters 2016)

Most of the time, parents can safely feed peanuts to babies on their own, but infants with a history of allergies should still get a checkup first, a research review confirms.

"If your infant has a history of an allergic disorder (i.e. eczema, food allergy), we would recommend that he/she be evaluated for a peanut allergy by an allergist, before introducing a peanut containing product at home," said lead study author Dr. Sara Anvari of Texas Children's Hospital and Baylor College of Medicine in Houston.

"Also, when introducing peanuts at home, do not introduce whole peanuts as they can be a choking hazard," Anvari added by email.

Reports of peanut allergies have increased more than three-fold among U.S. children in the last 20 years, Anvari and colleagues note in JAMA Pediatrics.

During this time, feeding guidelines have moved away from telling parents to avoid introducing some foods that can cause allergies until kids are 2 or 3 years old, and stopped telling women to avoid peanuts when they're pregnant or nursing. But many recommendations still stop short of urging parents to give babies eggs and peanuts early in life.

For the current analysis, researchers summarized research published since 2008, when the American Academy of Pediatrics (AAP) revised its guidelines for peanut introduction to note there's no evidence to suggest waiting longer than six months could reduce the risk for allergies to this food.

After these guidelines and other similar recommendations came out, a shift in thinking about peanuts came courtesy of a study of 640 babies in the U.K. who were already at high risk for nut allergies because they had eczema or an egg allergy already, researchers note.

This U.K. experiment compared the effects of giving some babies a 6-gram dose of peanut each week to strict peanut avoidance in children over a five-year period. All of the kids in the study got skin tests to determine if they developed a peanut allergy.

At age 5, about 14 percent of the kids who avoided nuts had a peanut allergy compared with roughly 2 percent of the children who got an early taste of this food.

Based on these results, some proposed guidelines may be shifting toward early introduction of peanuts even in babies with a history of other allergies, the authors note.

But when these high risk babies get that first taste of peanuts, they should have it in a clinical setting with lab tests to check for allergic reactions before parents offer peanuts to children at home, the researchers point out.

This study had some limitations, including a lack of data on how much peanuts babies could have at one time or how long they might need to continue eating nuts on a regular basis to protect against allergies. It's also unclear what risks babies might face if they got a taste of peanuts then stopped eating them.

Still, guidelines in development from the National Institute of Allergy and Infectious Diseases are expected to come out soon and recommend that all kids get their first taste of peanuts around 4 to 6 months of age as long as they have tried some other foods first, said Dr. Matthew Greenhawt, a food researcher at the University of Colorado School of Medicine who wasn't involved in the current analysis.

"Guidance regarding when to introduce peanut into the diet of an infant is changing, based on new research that shows that early introduction around 4 to 6 months of life, after a few other foods have been introduced into the infant's diet, is associated with a significantly reduced risk of such infants developing peanut allergy," Greenhawt added by email. "This is an amazing opportunity to help potentially reduce the number of cases of peanut allergy."

Babies, however, should stick to nut butters and pastes, said Dr. Robert Boyle, a pediatric allergy researcher at Imperial College London who wasn't involved in the current analysis.

"Whole nuts are not advised for babies or children up to the age of 3, due to the risk of choking," Boyle added by email.