A small dish of peanuts on a kitchen surface
For two decades, parents were told to delay peanuts. The evidence now points the opposite way: early, sustained introduction in the first year of life is one of the most effective allergy-prevention strategies in pediatrics.

Few areas of clinical medicine have reversed course as completely as peanut allergy prevention. For most of the 2000s, guidance in the US encouraged delaying peanut introduction in infants thought to be at risk. That advice, it turned out, was almost exactly backwards. A landmark randomized trial published in 2015 showed that introducing peanut early, rather than avoiding it, cut the rate of peanut allergy by roughly 80% in high-risk infants, and the field has been rebuilt around that finding ever since.

A June 2026 New England Journal of Medicine Clinical Practice article by Du Toit and Lack presents the current state of evidence on prevention and treatment, anchored to a clinical case. It is an unusually clean story for a consumer-health topic: the prevention strategy is strongly supported by trial data, and for the first time there are FDA-approved treatments rather than only avoidance and emergency epinephrine. This article walks through what the data actually show, and where the limits still are.

The Prevention Reversal: From Avoidance to Early Introduction

Peanut allergy affects an estimated 2 to 2.5% of children in Western countries, and prevalence rose sharply over the preceding two decades. The old logic, that avoiding an allergen early would prevent sensitization, was intuitive but never well supported by trial evidence. For most of the 2000s it was nonetheless the official position: in 2000 the American Academy of Pediatrics recommended that high-risk infants avoid peanuts for the first three years of life, and that nursing mothers do the same. The guidance was widely followed.

The epidemiological crack in that logic came from a simple observation: Jewish children in the UK, who typically avoided peanut in infancy per Western guidance, had markedly higher rates of peanut allergy than genetically similar Jewish children in Israel, where a peanut-based snack called Bamba is introduced in the first year of life. The obvious implication was that avoidance was not protecting children — it may have been making things worse.

By 2008 the AAP had already walked back its 2000 stance, acknowledging there was insufficient evidence that avoidance prevented allergy and quietly dropping the recommendation. But dropping an avoidance guideline is not the same as recommending active early introduction, and clinical practice remained uncertain and inconsistent for years after. The history of these shifting guidelines is a useful case study in how well-intentioned clinical advice, issued ahead of the evidence, can have the opposite of its intended effect at a population level.

The Learning Early About Peanut Allergy (LEAP) trial (Du Toit et al., NEJM, 2015) finally settled the question with a randomized design. It enrolled more than 600 high-risk infants (those with severe eczema, egg allergy, or both) and randomized them to either consume or avoid peanut until age 5. The result was decisive: among children who started with a negative skin-prick test, peanut allergy at age 5 was 13.7% in the avoidance group versus 1.9% in the consumption group, a relative reduction of roughly 80%.

Two follow-up questions mattered. First, was the protection durable, or did it depend on continuous eating? The LEAP-On study (NEJM, 2016) had participants avoid peanut for 12 months after the trial ended and found the protection largely persisted, suggesting early introduction induces lasting tolerance rather than merely suppressing reactions. Second, does it last into later childhood? The LEAP-Trio follow-up (NEJM Evidence, 2024) tracked participants into adolescence and reported a sustained reduction in peanut allergy of roughly 71% in the early-introduction group, years after the intervention ended.

On the strength of LEAP, expert guidance changed. The 2017 NIAID Addendum Guidelines recommended risk-stratified early introduction: infants with severe eczema or egg allergy should have peanut introduced as early as 4 to 6 months (after evaluation where appropriate), while lower-risk infants can have it introduced freely around the same window. This is now the standard of care, and it is the single most important takeaway for parents.

The Claim

“Peanut allergy is now both preventable and treatable: feeding peanut early prevents most cases, and approved therapies can protect children who are already allergic.”

(Composite claim reflecting current clinical guidance and coverage of recent FDA approvals.)

Treatment: Oral Immunotherapy and Palforzia

Prevention does not help the children who are already allergic. For them, the management standard was for decades strict avoidance plus injectable epinephrine for accidental exposure. That changed with oral immunotherapy (OIT), in which a patient consumes gradually increasing, carefully measured doses of peanut protein to raise the threshold at which a reaction occurs.

The pivotal trial was PALISADE (NEJM, 2018), which tested a standardized peanut-derived drug, AR101. After roughly a year of treatment, about 67% of participants aged 4 to 17 could tolerate a 600 mg challenge dose (around two peanuts) versus 4% on placebo. On that basis the FDA approved the product as Palforzia in January 2020, the first approved treatment for peanut allergy.

The crucial distinction, often lost in coverage, is that OIT is not a cure and does not allow free eating. Its goal is desensitization: raising the reaction threshold enough to protect against accidental exposure, not enabling a patient to eat peanut products at will. Protection generally depends on continued daily dosing, and the treatment itself causes allergic reactions in a meaningful share of patients, including some cases of anaphylaxis during dosing. It is a structured medical therapy with real risks, not a casual desensitization.

The Newest Option: Omalizumab

In February 2024 the FDA approved omalizumab (Xolair) to reduce allergic reactions to multiple foods, including peanut, after accidental exposure. Omalizumab is an anti-IgE monoclonal antibody already used in asthma and chronic urticaria; rather than retraining tolerance to a specific food, it dampens the IgE-driven allergic response broadly.

The approval rested on the OUtMATCH trial (Wood et al., NEJM, 2024), in which omalizumab raised the amount of peanut protein (and other foods) participants could tolerate without reaction substantially more than placebo. As with OIT, the framing matters: omalizumab is protection against accidental exposure for people with food allergy, administered by injection, not a license to eat the offending food. It also covers multiple foods at once, which is its main advantage over food-specific OIT for patients with several allergies.

Approach Goal Key Evidence Status
Early introduction Prevent allergy from developing LEAP (~80% reduction); LEAP-Trio (~71% into adolescence) Standard of care (NIAID 2017)
Oral immunotherapy (Palforzia) Desensitize; protect vs. accidental exposure PALISADE (~67% tolerated 600 mg vs. 4% placebo) FDA approved (2020), ages 4–17
Omalizumab (Xolair) Reduce reactions across multiple foods OUtMATCH (raised tolerated dose vs. placebo) FDA approved (2024), ages 1+
Epicutaneous immunotherapy (Viaskin Peanut) Desensitize via skin patch in toddlers EPITOPE Phase 3 (effective vs. placebo in ages 1–3) Not FDA approved; under regulatory review

What the Evidence Actually Shows

Both halves of the claim hold up, with one important qualification. Prevention through early introduction is supported by high-quality randomized evidence with a large, durable effect, and it is now formal guideline-based care. Treatment is real but more limited: the approved therapies reduce the risk and severity of reactions to accidental exposure, they are not cures, they require ongoing administration, and they carry their own risk of allergic reactions. “Preventable” is strongly supported; “treatable” is true in the specific sense of risk reduction, not free eating.

What This Means for Parents and Patients

For parents of infants, the practical guidance is clear and well-evidenced: do not delay peanut. For lower-risk babies, age- appropriate peanut-containing foods can be introduced around 4 to 6 months alongside other solids. For infants with severe eczema or egg allergy, the NIAID guidelines recommend early introduction as well, with clinical evaluation first where indicated. Whole peanuts are a choking hazard for infants; smooth peanut butter thinned into other foods, or dissolvable peanut puffs, are the usual vehicles.

For families of children who are already allergic, the message is that options now exist beyond avoidance, but they are medical therapies to discuss with an allergist, not consumer products. OIT and omalizumab both reduce the danger of accidental exposure; neither removes the underlying allergy or the need for an epinephrine auto-injector. The choice between them, or whether to pursue either, depends on the child's age, number of food allergies, and tolerance for the treatment burden.

Several questions remain genuinely open. The long-term durability of OIT-induced desensitization after stopping treatment is still being defined. A third delivery approach, epicutaneous immunotherapy (EPIT), has Phase 3 data: the EPITOPE trial (Greenhawt et al., NEJM, 2023) showed the Viaskin Peanut patch was effective and well-tolerated in toddlers aged 1–3, with patch-site reactions as the primary adverse effect. It has not yet received FDA approval and remains under regulatory review. But the central facts are no longer in doubt: the avoidance era was a mistake, and early introduction is one of the clearest prevention wins in modern pediatrics.

Verdict: Supported

The prevention strategy is backed by randomized trial evidence of unusual strength: LEAP showed roughly an 80% reduction in peanut allergy from early introduction, LEAP-On showed the protection persists, and LEAP-Trio showed it holds into adolescence. Treatment is now real, with two FDA-approved options (Palforzia, 2020; omalizumab, 2024) demonstrated in randomized trials to reduce reactions to accidental exposure. The one caveat that keeps this from a perfect score for the average reader is interpretation: treatments protect against accidental exposure and are not cures or licenses to eat peanut freely. Evidence rating: 5/5.

References & Further Reading