Most infants with peanut, egg allergy try tree nuts, but some do not for fear of reaction

Eighty-five percent of infants with peanut and/or egg allergy had at least one type of tree nut introduced into their diet by age 3 years, according to a study published in The Journal of Allergy and Clinical Immunology: In Practice.

However, 25% of children with peanut allergy never had tree nuts introduced, which is a concern given they are at greater risk for developing a tree nut allergy, which early introduction may prevent, Julia Payne, MBBS, of Population Allergy Group at Murdoch Children’s Research Institute in Victoria, Australia, and colleagues wrote.

The researchers identified 94 patients who were diagnosed with peanut (n = 16) or egg allergy (n = 72) or both (n = 9) at age 12 months or younger and followed up with their caregivers by phone between age 18 and 42 months (median follow-up age, 35 months).

Anaphylaxis occurred among 10 patients due to egg and three due to peanut.

During follow-up, 57 caregivers said that their clinician had advised them to introduce their infant to tree nuts, including almond, hazelnut, cashew, pistachio, walnut, pecan, Brazil nuts and macadamia, in addition to pine nut.

Also, 14 infants had skin prick testing for tree nuts, including three of the patients with a history of anaphylaxis, with more frequent screenings among the infants with peanut allergy vs. those with egg allergy (37% vs. 11%; P = .01).

At baseline, 18 infants already had one or more tree nuts introduced into their diets, with four experiencing a reaction, although none experienced anaphylaxis.

At follow-up, 75% of infants with peanut allergy, 87% of the infants with egg allergy (n = 69) and 89% of the infants with allergies to both had one or more tree nuts introduced into their diets.

Among the 80 of 94 families that had introduced one or more tree nuts into their infants’ diets, seven reported a reaction such as rash, swelling, hives, vomiting, sneezing, lethargy and oral irritation, with none requiring epinephrine.

Reactions most often were associated with cashew (n = 4 of 6), including one reaction involving lethargy that resolved without epinephrine. The most frequently introduced tree nut was almond, which only led to one reaction in 73 children.

The most common reason for not introducing infants to tree nuts at home was a lack of tree nuts in the family’s routine diet. The least commonly consumed tree nuts were Brazil nuts and pecans.

Fear of an allergic reaction was the second most common reason overall and the primary reason among caregivers of infants with peanut allergy for not introducing tree nuts into the infant’s diet.

Specifically, 48% of parents of children with peanut allergies compared with 30% of parents of children with egg allergies (P = .002) were worried about reactions to tree nuts regardless of the type of tree nut.

Further, the researchers noted that cultural practices and socioeconomic status may influence the introduction of tree nuts into children’s diets and that clinicians should be aware of these factors.

The researchers also warned that the 25% of children with peanut allergy who had not been introduced to tree nut may be more susceptible to tree nut allergy, adding that additional studies are needed to determine how best to introduce tree nuts to infants with higher risk.