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Preventing peanut allergy in infants: Follow the evidence

Peterson, Kathleen, PhD, RN, PCPNP-BC; Barbel, Paula, PhD, RN, PNP

doi: 10.1097/01.NURSE.0000534093.48992.33
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Recent studies on how peanut allergies develop in children have led to new guidelines regarding the introduction of peanut-containing foods to infants. This article reviews the evidence behind these guidelines and discusses how clinicians should apply them.

Kathleen Peterson is a professor of nursing and Paula Barbel is an assistant professor of nursing at The College at Brockport, State University of New York, Brockport, N.Y.

The authors have disclosed no financial relationships related to this article.

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PEANUT ALLERGY usually develops early in life and is rarely outgrown as one ages. Peanut allergy rates are highest (1% to 2%) in Westernized countries such as the United States, United Kingdom (U.K.), Canada, and Australia. Most allergic reactions to peanuts are immunoglobulin E (IgE) mediated and may lead to serious reactions, including anaphylaxis.1 For these reasons, experts once recommended excluding peanut-based foods from infants' diets to reduce the risk of triggering peanut allergy. But due to emerging evidence, these guidelines have been dramatically revised: Experts now recommend introducing peanut-based food to most infants at an early age. This article reviews the evidence behind the current guidelines and discusses how clinicians should apply them.

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Evidence reveals flaws in prior guidelines

Intending to prevent development of peanut allergy in children, the U.K. in 1998 and the United States in 2000 established clinical practice guidelines that excluded peanuts from the diet of infants and from mothers during pregnancy and lactation for any infant who was at high risk for allergy based on factors discussed below.2 Surprisingly, however, the percentage of children with peanut allergy in Western countries didn't decrease subsequently. In fact, it doubled from 2004 to 2014, increasing from 1.4% to 3.0%.2 In the same period, the risk of developing peanut allergy was found to be 10 times greater in children who were of Jewish descent living in the U.K. compared with children with the same ancestry living in Israel.3 In contrast to children in the U.K. who had no peanut-based food during the first year of life, Israeli children were typically introduced to peanut-based food at about 7 months.

A landmark randomized controlled study called Learning Early About Peanut Allergy (LEAP) was conducted to investigate this disparity.2 Over 600 infants were enrolled from December 2006 to May 2009. The infants studied were between ages 4 and 11 months and considered to be at high risk of peanut allergy due to severe eczema, egg allergy, or both.

The infants were grouped into two study cohorts according to results of a skin-prick test for peanut allergy (no measurable wheal after testing versus a wheal measuring 1 to 4 mm in diameter). Infants in each study cohort were then randomly assigned to a group in which infants consumed dietary peanut products or a group in which infants would avoid consuming peanut products. The primary outcome was the proportion of infants with peanut allergy at age 60 months. The results revealed that early introduction of peanuts significantly decreased the development of peanut allergies in these high-risk children and modulated immune responses to peanuts.2

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The investigators of the LEAP study then conducted a 12-month extension of the LEAP trial, the Persistence of Oral Tolerance to Peanut (LEAP-ON) study.4 The intent of this study was to investigate the mechanisms of loss of protection from allergic responses. Caregivers of infants in the group from the LEAP study who'd been introduced to peanuts early and consumed peanuts until age 60 months were asked to not feed the infants peanuts for 12 months. The research showed that even after a year of not consuming peanut products, the prevalence of peanut allergy in this group was 74% lower than the prevalence in the group that avoided peanuts for the first 60 months of life. The investigators concluded that avoiding peanuts for 12 months wasn't associated with an increase in the prevalence of peanut allergy.4

In a separate study, Koplin and colleagues used data from a large-scale, population-based cohort study known as the HealthNuts study to assess the prevalence and risk factors for allergic disease in early childhood.5 The sample for this epidemiologic study consisted of 5,276 1-year-old infants. Results suggested that many more infants than those with severe eczema, egg allergy or both, would benefit from early introduction of peanut products, and that doing so could decrease the incidence of peanut allergy in children.5

The LEAP studies as well as the study conducted by Koplin and colleagues provided evidence that peanut allergy could be prevented through introduction of peanut-containing foods much earlier than suggested in previous practice guidelines. An Expert Panel was established to develop evidence–based recommendations for the dietary introduction of peanut-containing food to prevent development of peanut allergy.6

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New recommendations

To reduce the risk of peanut allergy, the Expert Panel recommended introducing peanut butter safely to infants with varying degrees of potential allergy at the time when the infant is developmentally ready for the introduction of solid food.6 Addendum guidelines published in 2017 and endorsed by the American Academy of Pediatrics (AAP) present three different recommendations on the introduction of peanut-containing foods based on the infant's risk for development of peanut allergy (see Current guidelines on the introduction of peanut-containing foods to infants).

Importantly, the Expert Panel stated that in each of the situations, solid foods other than peanut-containing foods should be introduced to the infant first; for example, infant cereal, pureed bananas, or pureed prunes. This ensures that the infant is developmentally ready for solid foods.6 When introducing a solid food to an infant, parents should wait 2 to 3 days before starting another new food.7

The Expert Panel also suggests that infants in the category of severe eczema, egg allergy, or both, have peanut-specific IgE (peanut sIgE) measurement, skin prick testing (SPT), or both before the introduction of peanut-containing foods.6 The resulting level of peanut sIgE then places the infant into one of two categories for further direction and care (see Recommended evaluation for infants with severe eczema, egg allergy, or both).

Addendum guidelines established by the Expert Panel include a list of age-appropriate forms of peanuts, as whole peanuts are a choking hazard to infants and young children, as well as excellent instructions for home feeding for infants at low risk for developing a peanut allergy.6 For example, smooth peanut butter can be introduced to infants by mixing it with a small amount of cereal and yogurt or by dissolving peanut butter puffs in breast milk or formula.7 Either mixture can then be fed by spoon.

Current guidelines also recommend that infants who are at high risk for developing allergies be fed 6 to 7 g of peanut butter per week divided into three or more feedings because delaying the introduction of peanut may be associated with an increased risk of peanut allergy. Infants at lower risk can consume peanut butter according to family and cultural practices.8,9 For a summary of recommendations, see General guidelines for introduction of peanut-containing foods at home for infants at low risk of developing peanut allergy.

Clinical randomized trials are underway to evaluate the benefit of the early introduction of eggs for infants in the hope of finding similar results. A large observational study in Israel found that infants introduced to cow's milk in the first 21 days of life had a lower chance of developing a milk allergy compared with infants introduced to milk at ages 3 and 6 months.10 Further research is likely to lead to updated recommendations for the early introduction of food allergens such as egg and milk in the near future.

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Patient education

Nurses need to share these new guidelines with parents of infants. This education can start in the prenatal period and continue in primary and tertiary care offices and institutions. When teaching parents about these guidelines, emphasize that solid foods aren't safe for infants before ages 4 to 6 months because of the suck/swallow, tongue thrust, and gag reflex that are strong in the first 4 months of life.11 In addition, according to the AAP, the introduction of solid foods before age 4 months is associated with increased weight gain in infancy and early childhood.12 For more information about peanut allergy and details about introducing food to infants, advise patients to visit the AAP website at www.healthychildren.org and search for “peanut allergy.”

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General guidelines for introduction of peanut-containing foods at home for infants at low risk of developing peanut allergy6,8,9

  • Peanut butter should not be the first solid food introduced.
  • Introduce peanut butter only when the infant is healthy.
  • Give the first peanut butter feeding at home, rather than at day care or a restaurant.
  • Ensure that one adult care provider is available to focus all attention on the infant when peanut butter is introduced.
  • Prepare a full portion of peanut-containing foods. For example, per Option 2 from the addendum guidelines: 2 teaspoons of smooth peanut butter and 2 to 3 teaspoons of hot water, mixed well and cooled; more water may be added as needed, or add to infant cereal if previously tolerated.
  • Offer the infant a small part of the serving on the tip of a spoon.
  • Wait 10 minutes. Monitor the infant for signs and symptoms of an allergic reaction, such as a new rash or a few urticaria around the mouth or face. A more severe reaction may be indicated by the following signs and symptoms (either alone or in combination): lip, facial or tongue edema, vomiting, widespread urticaria or welts over the body, repetitive coughing, wheezing, change in skin color to blue or gray, difficulty breathing, sudden fatigue, lethargy, or going limp. Immediately call 911 if the infant has any signs or symptoms of a severe reaction.
  • If the infant has no signs or symptoms of an allergic reaction, slowly give the rest of the peanut-containing food at the infant's usual eating speed.
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REFERENCES

1. Wang J. Peanut, tree nut, and seed allergy: clinical guidelines. UpToDate. 2017. http://www.uptodate.com.
2. Du Toit G, Roberts G, Sayre PH, et al Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 2015;372(9):803–813.
3. Du Toit G, Katz Y, Sasieni P, et al Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy. J Allergy Clin Immunol. 2008;122(5):984–991.
4. Du Toit G, Sayre PH, Roberts G, et al Effect of avoidance on peanut allergy after early peanut consumption. N Engl J Med. 2016;374(15):1435–1443.
5. Koplin JJ, Peters RL, Dharmage SC, et al Understanding the feasibility and implications of implementing early peanut introduction for prevention of peanut allergy. J Allergy Clin Immunol. 2016;138(4):1131–1141. e2.
6. Togias A, Cooper SF, Acebal ML, et al Addendum guidelines for the prevention of peanut allergy in the United States: report of the National Institute of Allergy and Infectious Diseases-sponsored expert panel. Ann Allergy Asthma Immunol. 2017;118(2):166.e7–173.e7.
7. Cox A. When can I start giving my baby peanut butter? American Academy of Pediatrics. 2017. http://www.healthychildren.org.
8. Fleischer DM. Life after LEAP: how to implement advice on introducing peanuts in early infancy. J Paediatr Child Health. 2017;53(suppl 1):3–9.
9. Fleischer DM, Sicherer S, Greenhawt M, et al Consensus communication on early peanut introduction and the prevention of peanut allergy in high-risk infants. Ann Allergy Asthma Immunol. 2015;115(2):87–90.
10. Greenhawt M. The National Institutes of Allergy and Infectious Diseases sponsored guidelines on preventing peanut allergy: a new paradigm in food allergy prevention. Allergy Asthma Proc. 2017;38(2):92–97.
12. American Academy of Pediatrics. Infant food and feeding. 2018. http://www.aap.org.
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