Allergy testing for toddlers: food sensitivity and what parents should know
Food allergies and sensitivities in toddlers can be stressful for both the child and their parents. At this stage of life, children are still developing their immune systems, and their reactions to certain foods can vary widely—from mild skin rashes to severe, life-threatening responses.
Understanding the types of tests available, their accuracy, and what steps to take is crucial for proper diagnosis and management.
Food allergy vs. food sensitivity
Before diving into testing, it’s important to understand the distinction:
Food allergy: An immune system reaction that occurs shortly after eating a particular food. Even small amounts can trigger symptoms such as hives, swelling, vomiting, breathing difficulty, or anaphylaxis. Common culprits include milk, eggs, peanuts, tree nuts, wheat, soy, fish, and shellfish.
Food sensitivity/intolerance: Unlike allergies, sensitivities do not involve the immune system in the same way. They may cause delayed or mild reactions such as stomach upset, bloating, eczema flare-ups, or irritability. For example, lactose intolerance is a sensitivity, not an allergy.
Signs of food allergies in toddlers
Symptoms of a food allergy often appear quickly (within minutes to 2 hours). Watch for:
Hives or skin rash
Swelling of lips, eyes, or face
Vomiting or diarrhoea
Coughing, wheezing, or difficulty breathing
Extreme fussiness or inconsolable crying after eating
Food sensitivities, however, may take longer to show up and include:
Gas, bloating, or stomach pain
Loose stools or constipation
Eczema flare-ups
Sleep disturbances
Behavioural changes after eating
Common food allergies in toddlers and their symptoms
Certain foods are responsible for the majority of allergic reactions in children. Here are the most common ones:
Cow’s milk
Symptoms: Hives, vomiting, diarrhoea, bloody stools, eczema flare-ups, irritability after feeding.
Milk allergy is the most common in infants and toddlers, often appearing within the first year of life. Some children outgrow it by school age.
Eggs
Symptoms: Skin reactions (hives, rashes), stomach cramps, vomiting, nasal congestion, or wheezing.
Egg allergies usually involve the whites but can also occur with yolks. Many children outgrow this allergy by age 5–6.
Peanuts
Symptoms: Hives, facial swelling, difficulty breathing, anaphylaxis in severe cases.
Peanut allergies are often long-lasting and can be life-threatening. They require strict avoidance.
Tree nuts (almonds, walnuts, cashews, etc.)
Symptoms: Similar to peanuts—rashes, swelling, vomiting, breathing problems, or anaphylaxis.
Cross-reactivity is common, meaning if a child is allergic to one nut, they may also react to others.
Soy
Symptoms: Hives, runny nose, stomach upset, diarrhoea, and eczema.
Often found in processed foods, which makes avoidance tricky. Some children outgrow it.
Wheat
Symptoms: Hives, digestive issues, nasal congestion, or in rare cases, anaphylaxis.
Must be distinguished from celiac disease, which is an autoimmune condition triggered by gluten.
Fish
Symptoms: Hives, swelling, stomach upset, wheezing, or severe reactions.
Fish allergies tend to persist into adulthood and may apply to one or multiple species.
Shellfish (shrimp, crab, lobster, etc.)
Symptoms: Hives, vomiting, swelling, coughing, and potential anaphylaxis.
Typically lifelong, shellfish allergies are among the most severe.
Types of allergy testing for toddlers
Skin prick test (SPT)
A small amount of allergen extract is placed on the skin (usually the forearm or back) and lightly pricked.
If the toddler is allergic, a raised bump (similar to a mosquito bite) will appear.
Pros: Fast results (within 15–20 minutes), widely used, inexpensive.
Cons: Can be uncomfortable, may produce false positives, and requires specialist supervision.
Blood test (IgE test / RAST or ImmunoCAP)
Measures the level of allergy-related antibodies (IgE) in the blood against specific foods.
Pros: No skin pricking, safer for children with severe eczema or asthma, results not affected by antihistamines.
Cons: Requires a blood draw, may be less precise, results can take several days.
Oral food challenge (OFC)
The toddler is fed the suspected allergen in gradually increasing amounts under close medical supervision.
Considered the gold standard for diagnosing food allergies.
Pros: Most accurate way to confirm or rule out an allergy.
Cons: Risk of severe reactions, only performed in a clinical setting.
At-home sensitivity tests (not recommended)
Hair, saliva, or finger-prick blood tests marketed online for food sensitivities are not scientifically validated.
These often measure IgG antibodies, which only indicate food exposure, not an allergic reaction.
Paediatricians and allergists do not recommend these for diagnosing food issues.
When to consider testing
Testing should be discussed with your paediatrician if your toddler shows:
Repeated or severe reactions after eating certain foods
Persistent eczema that does not improve with treatment
Chronic digestive issues linked to meals
Family history of severe allergies
Do not remove multiple foods from your toddler’s diet without medical advice. Restrictive diets at this age can lead to nutrient deficiencies.
Preparing for a toddler’s allergy test
Medical history: Your child’s doctor will ask about reaction timing, food triggers, and family history.
Medications: Antihistamines may need to be stopped before a skin prick test. Always ask your doctor.
Comfort: For blood draws or skin tests, bring a favourite toy or blanket to ease anxiety.
Managing food allergies or sensitivities
If an allergy is confirmed:
Avoid the trigger food completely.
Learn to read ingredient labels carefully.
Ask your paediatrician if you should carry an epinephrine auto-injector (EpiPen).
Work with a registered dietitian to ensure your toddler gets balanced nutrition.
If it’s a sensitivity rather than an allergy:
Tolerance levels may vary; some children can handle small amounts.
Keep a food diary to track symptoms.
Discuss with your paediatrician whether foods should be reduced, avoided, or reintroduced later.
Introducing new foods to toddlers safely
Introducing new foods is an important part of development, but it can be nerve-wracking if you’re worried about allergies. Here are safe practices backed by paediatric guidelines:
Start around 6 months
Most babies can begin solids around 6 months. Delaying allergenic foods (like peanuts or eggs) beyond this age does not prevent allergies.
Introduce one food at a time
Wait 3–5 days before introducing another new food. This makes it easier to spot reactions.
Start with small amounts
Begin with a tiny portion (like a small spoonful) and watch for reactions for at least 2 hours.
Introduce high-risk foods early
Research shows that early introduction of peanuts and eggs (around 6–12 months) may actually reduce the risk of developing allergies—especially in high-risk children (those with eczema or existing food allergies).
Avoid whole nuts and choking hazards
Serve allergenic foods in safe forms—such as smooth peanut butter thinned with water or mashed egg yolk. Whole nuts and chunky nut butters are choking risks for toddlers.
Know the emergency plan
If your child has shown any allergic reaction before, talk with your paediatrician before reintroducing foods.
Keep antihistamines handy, and if your doctor prescribes an epinephrine auto-injector, always carry it.
Key takeaways
True food allergies in toddlers are immune-based and can be serious, while food sensitivities cause discomfort but are not life-threatening.
Reliable testing includes skin prick tests, blood tests, and oral food challenges under medical supervision.
At-home sensitivity kits are not reliable and should not guide dietary changes.
The most common toddler food allergies include milk, eggs, peanuts, tree nuts, soy, wheat, fish, and shellfish.
Always involve a paediatrician or paediatric allergist before testing or eliminating foods.
