Tree nut allergy in babies

Tree nut allergy: the basics

Tree nuts include almonds, Brazil nuts, cashews, hazelnuts, pecans, pistachios and walnuts (AAAAI). The AAAAI estimates that tree nut allergy affects about 0.5% to 1% of people in the US. It happens when the immune system overreacts to proteins in the nut.

Along with peanut and shellfish, ACAAI says tree nuts are among the foods most often linked to anaphylaxis. And unlike milk or egg allergy, tree nut allergy usually lasts for life: ACAAI says fewer than 10% of people outgrow it, and the AAAAI gives about 10%.

Peanuts aren’t tree nuts. They’re legumes that grow underground. Still, ACAAI says 25% to 40% of people with peanut allergy also react to at least one tree nut. A tree nut allergy doesn’t necessarily mean a peanut allergy (AAAAI).

Which foods count as tree nuts

In the US, the FDA’s 2025 guidance lists the tree nuts that count as major allergens on labels: almond, Brazil nut, cashew, hazelnut (filbert), macadamia, pecan, pine nut, pistachio and walnuts (including black walnut).

Coconut is no longer on that list. Since January 2025, the FDA no longer treats coconut as a major food allergen, so it shouldn’t appear in a “Contains” statement, though it must still be listed in the ingredients. Some older packaging may still show it in a “Contains” statement for a few years (FDA). The AAAAI says the vast majority of people with tree nut allergy can eat coconut, which is a fruit, not a true nut. Reactions to coconut do happen, so ACAAI says to talk to your allergist first if your child has a tree nut allergy. See coconut.

Introducing tree nuts

Tree nuts can go in with your baby’s other first foods, from around 6 months. The NHS lists nuts among the foods that can trigger allergy and can be introduced from around 6 months, one at a time, served finely ground or as nut butter. The AAP lists nut products with egg, peanut and the other allergens, once your baby has managed a few lower-risk first foods, and gives about 2 teaspoons of a nut butter such as cashew butter as a regular portion.

Safe forms:

• Smooth nut butter, thinned. Stir a little smooth almond butter or cashew butter with hot water until runny, let it cool, and serve it on a spoon or stirred into porridge, purée or yogurt your baby already eats. Or spread it thinly on soft toast strips once wheat has gone well.
• Finely ground nuts stirred into food, such as ground walnuts, cashews, hazelnuts, pecans or pistachios. Brazil nuts are the exception: one nut can have more selenium than the NIH upper limit for a baby up to 6 months, so they wait until 7 months, and then only a tiny finely grated amount. Use another tree nut for the first taste.

Never give whole or chopped nuts, or spoonfuls or chunks of nut butter. The CDC lists all of these as choking hazards. The AAP says to avoid whole nuts until at least age 4, and the NHS says no whole nuts for children under 5. See whole nuts and the choking hazards list.

Offer each new nut on a day your baby is well, at home, when you can watch them for a couple of hours afterward. Start with a small amount, and if there’s no reaction, build up over the next few servings. Mixed nut butters make it harder to tell what caused a reaction, so single-nut butters are simpler at first. Then keep the nuts your baby tolerates in their diet: see keeping allergens in the diet.

Talk to your doctor first if your baby has severe eczema, an egg allergy, a peanut allergy, or has already reacted to a food (AAP, ACAAI). Ask how and when to introduce tree nuts, not about putting them off. See also how to introduce peanut.

Signs of tree nut allergy

Reactions usually start within minutes of eating, but can take up to 2 hours (NHS).

Mild to moderate (ACAAI, NHS):

• hives or a red, itchy rash, or itching around the mouth
• mild puffiness of the face or around the eyes
• vomiting once, tummy pain or diarrhea
• sneezing, or a stuffy or runny nose

If it’s only one of these, stop offering that nut, stay with your baby and watch them closely for the next couple of hours, and call your pediatrician before you offer it, or any other nut, again. If signs show up in more than one part of the body at once, treat it as anaphylaxis (below).

Signs of anaphylaxis are trouble breathing, wheezing or a cough that won’t stop, swelling of the tongue or throat, lips or mouth that suddenly swell, a hoarse cry, turning pale or floppy, becoming very sleepy or unresponsive, or signs in more than one part of the body at once. If you see any of these and your baby has an epinephrine (adrenaline) auto-injector, use it right away, then call for an ambulance. Call 911.Call 999.Call your local emergency number (such as 112 in Europe or 000 in Australia). If you don’t have an auto-injector, call straight away. Keep your baby lying down, never standing or walking (on their side if they’re vomiting, head and shoulders a little raised if breathing is hard), and go to hospital even if they seem better. See signs of anaphylaxis.

How tree nut allergy is diagnosed

Your doctor or an allergist will ask about past reactions and may arrange a skin prick test or a blood test for IgE (ACAAI). If the results aren’t clear, the allergist may suggest an oral food challenge: tiny, increasing amounts of the nut given under strict supervision. The AAAAI says every food challenge should be done in a medical facility, supervised by an allergist. Don’t try one at home.

One nut or all of them?

Some tree nuts are closely related: the AAAAI names cashew with pistachio and pecan with walnut. Children allergic to one tree nut are often allergic to more than one, but it may be safe to eat some while avoiding others.

That decision belongs with your allergist, who will weigh your child’s age, test results and the risk of cross-contact (AAAAI). ACAAI says allergists usually advise avoiding all nuts. Don’t try a new nut at home to “see” after a reaction. The AAAAI adds that people with tree nut allergy can usually eat seeds such as sesame, sunflower and pumpkin, and often macadamia and pine nut, but ask your allergist first.

Living with tree nut allergy

• US labels must name the specific tree nut, such as “almonds” or “walnuts”, not just “tree nuts” (FDA).
• UK labels list “nuts” as one of 14 allergens, emphasized in the ingredients list, for example in bold (GOV.UK).
• Where nuts turn up. ACAAI lists baking mixes, breading, sauces, desserts and baked goods, Asian dishes, salads and ice cream toppings.
• Not just food. ACAAI says tree nut oils can be in lotions, hair products and soaps.
• “May contain” labels are voluntary (ACAAI, GOV.UK). Ask your allergist how to treat them.
• Peanut. ACAAI says allergists often advise people with tree nut allergy to avoid peanut too, because of cross-contact in factories. Ask your allergist what applies to your child.

When to see a doctor

Call your pediatrician or GP if:

• your baby has had any reaction to a tree nut, even a mild one
• your baby has a peanut allergy and you want to know how to introduce tree nuts

Don’t cut nuts or other major foods out on your own: the NHS says to talk to your health visitor or GP, who may refer you to a dietitian.

Where US and UK advice differs

• Whole nuts. The AAP says to avoid whole nuts until at least age 4, depending on the child. The NHS says no whole nuts for children under 5.
• How to serve nut butter. The AAP suggests thinning it into cereal, purée or yogurt. The NHS suggests spreading it on a food such as toast (we suggest spreading it thinly). Both say never give nut butter on its own.
• Who should check first. The NHS asks you to talk to your GP or health visitor before introducing any nut if there’s a history of food allergies or other allergies in your family. US guidance singles out severe eczema and egg or other food allergy.

For the other allergens, see how to introduce allergens and the safe first form of each one.