Food Allergies in Babies and Children
Content reviewed against published AAP, AAP, NIH, CDC guidelines
Last reviewed:
Food allergies occur when the immune system mistakenly identifies a food protein as harmful and mounts an immune response. They affect approximately 8% of children. The top 9 allergens (milk, egg, peanut, tree nuts, wheat, soy, fish, shellfish, sesame) account for most reactions. Reactions range from mild hives to life-threatening anaphylaxis. Early introduction of allergenic foods may prevent food allergy development.
Key takeaways
- Food allergies occur when the immune system mistakenly identifies a food protein as harmful and mounts an immune response.
- Duration: Milk allergy: ~80% outgrow by age 16. Egg allergy: ~70% outgrow by age 16. Peanut allergy: ~20% outgrow (usually by age 10 if they will). Tree nut, fish, and shellfish allergies are typically lifelong. Regular re-evaluation with testing recommended.
- Go to ER if: Signs of anaphylaxis: difficulty breathing, throat tightness, lip/tongue swelling
- No vaccine currently available
Symptoms
How It Presents by Age
0-6 months
Cow milk protein allergy (via formula or breast milk) is most common. May present as blood-streaked stools (FPIES/proctocolitis), severe eczema, vomiting, or irritability with feeds. Breastfed infants may react to allergens in maternal diet.
Risk level: Moderate — milk and egg most common at this age
6-12 months
First reactions often occur with introduction of solid foods. Egg, peanut, and milk are the most common triggers. Reactions typically occur within minutes of first or early exposures. Hives and vomiting are most common presentations.
Risk level: Moderate — critical window for both reactions and prevention
1-3 years
Peanut, tree nut, milk, and egg allergies are most common. Children may experience accidental exposures at daycare or social events. Many children outgrow milk and egg allergy by age 5. Peanut and tree nut allergies typically persist.
Risk level: Low to moderate
3-5 years
Most children with milk and egg allergy are outgrowing them. Peanut, tree nut, fish, and shellfish allergies tend to be lifelong. School/daycare management becomes important. May be able to tolerate baked milk or egg.
Risk level: Low to moderate (anaphylaxis risk persists)
Treatment
Strict allergen avoidance
The primary management for confirmed food allergies. Requires reading all food labels, understanding cross-contamination risks, and educating caregivers. Emergency plan should always be in place.
Epinephrine auto-injector
Every child with an IgE-mediated food allergy should have prescribed epinephrine (EpiPen Jr for 15-30 kg). Epinephrine is the first-line treatment for anaphylaxis. Train all caregivers on use. Replace before expiration.
Antihistamines
Cetirizine (Zyrtec) or diphenhydramine (Benadryl) for mild reactions (hives, itching only). NOT a substitute for epinephrine in anaphylaxis. Give while monitoring for progression.
Oral immunotherapy (OIT)
FDA-approved peanut OIT (Palforzia) for ages 4-17. Involves daily ingestion of gradually increasing allergen doses under medical supervision to raise the threshold for reaction. Does not cure allergy but can protect against accidental exposure.
Monitored introduction of baked forms
Many children with milk or egg allergy can tolerate extensively baked forms (baked in muffin/cake). Introduces allergen gradually and may accelerate natural tolerance. Must be done under allergist guidance.
Home Care
- Read EVERY food label carefully — allergens can be in unexpected products
- Develop a food allergy action plan with your allergist
- Carry epinephrine auto-injectors at all times (keep 2 available)
- Teach older children to recognize their allergens and symptoms
- Inform all caregivers, teachers, and family members about the allergy
- Clean surfaces that may have allergen residue before child eats
- Use "safe" recipes and identify allergy-friendly restaurants
- Wear a medical alert bracelet for children with severe allergies
- For breastfed infants with milk allergy: mother eliminates dairy from diet
When to Worry
Go to the ER if:
- Signs of anaphylaxis: difficulty breathing, throat tightness, lip/tongue swelling
- Give epinephrine FIRST, then call 911
- Child is dizzy, pale, or losing consciousness after food exposure
- Widespread hives with vomiting (multi-system reaction)
- Severe repeated vomiting 2-6 hours after eating (FPIES reaction)
- Infant is pale, limp, and lethargic after eating (FPIES shock)
- Any reaction where you gave epinephrine (always go to ER after epinephrine)
Call your doctor if:
- Suspected food allergy (hives, vomiting, or swelling after eating a specific food)
- Need for allergy testing referral
- Questions about when to introduce allergenic foods
- Mild reaction (hives only) that resolved with antihistamine
- Need for updated food allergy action plan
- Interest in oral immunotherapy or baked tolerance assessment
- Periodic re-evaluation to determine if allergy has been outgrown
Keep an eye on:
- Any reaction involving breathing difficulties (coughing, wheezing, throat tightness)
- Reaction involving 2+ body systems (skin + GI, or skin + respiratory)
- Facial or tongue swelling
- Child appears pale, limp, or confused after eating
- Repeated vomiting within 2-6 hours of eating (possible FPIES)
- Reaction is progressing or worsening
Prevention
- Introduce peanut-containing foods at 4-6 months in high-risk infants (those with severe eczema or egg allergy) — LEAP study evidence
- Introduce common allergens (egg, peanut, milk, wheat, sesame) early (4-6 months) and maintain regular exposure
- Breastfeeding — some protective evidence though not conclusive
- Do NOT delay introduction of allergenic foods — delay may increase risk
- Maintain regular consumption once introduced (at least 3 times per week)
- Optimize eczema treatment — broken skin barrier may allow sensitization
- Discuss early introduction with pediatrician, especially for high-risk infants
Contagion & Incubation
Incubation
Not applicable in the traditional sense. IgE-mediated reactions occur within minutes to 2 hours after ingestion. Sensitization (development of allergy) occurs over prior exposures. Non-IgE reactions (FPIES) can have delayed onset of 2-6 hours.
Contagious for
Not contagious.
Duration
Milk allergy: ~80% outgrow by age 16. Egg allergy: ~70% outgrow by age 16. Peanut allergy: ~20% outgrow (usually by age 10 if they will). Tree nut, fish, and shellfish allergies are typically lifelong. Regular re-evaluation with testing recommended.
Frequently asked questions
How long does food allergies last?
How does ige-mediated food allergy spread?
When should I take my baby to the ER?
Can ige-mediated food allergy be prevented?
When can my child return to daycare?
Sources
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources
Related Illnesses
Bottom line
Food Allergies is treatable with appropriate medical care. Seek emergency care if signs of anaphylaxis: difficulty breathing, throat tightness, lip/tongue swelling.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.