Food intolerances in children are conditions in which the body cannot properly process a food or one of its components, producing symptoms that are often not connected to diet. Unlike allergies (a rapid immune response that can be potentially serious), intolerances work through different mechanisms, cause delayed and dose-dependent symptoms, and rarely pose a life-threatening risk. However, their impact on a child's quality of life can be significant.

Intolerance vs. Allergy: The Key Distinction

Food allergy is mediated by the immune system (IgE antibodies): rapid response (minutes), potentially serious (anaphylaxis), not dose-dependent (even traces can trigger a reaction). Food intolerance is not IgE-mediated: slow response (hours or days), never life-threatening, often dose-dependent (small amounts may be tolerated). This distinction is critical because it changes management: a child with a milk allergy cannot consume even traces, while a child with lactose intolerance can often tolerate yogurt and aged cheeses.

Lactose Intolerance in Children: The Most Common

Lactose intolerance is caused by reduced production of lactase (the enzyme that digests lactose) in the small intestine. In children under 5 years old it's rare (nearly all infants produce lactase to digest breast milk). After age 5, in some populations (especially those of Mediterranean, Asian, or African descent), lactase activity tends to decrease naturally. Symptoms: bloating, gas, abdominal cramps, diarrhea occurring 30–120 minutes after milk ingestion. How it's diagnosed: hydrogen breath test (gold standard), elimination and reintroduction test. What it doesn't cause: joint pain, eczema, sleep problems, chronic fatigue (these symptoms are often attributed to lactose intolerance without scientific basis).

Non-Celiac Gluten Sensitivity in Children

Non-celiac gluten sensitivity (NCGS) is a controversial condition in children: symptoms (abdominal pain, fatigue, headache) improve with gluten elimination but celiac disease and wheat allergy have been ruled out. Diagnosis is one of exclusion and requires a complete diagnostic workup. Important: before eliminating gluten from your child's diet, rule out celiac disease with specific tests while your child is still consuming gluten. Undiagnosed celiac disease has serious long-term consequences; untreated NCGS has far fewer. Don't self-diagnose or self-prescribe a gluten-free diet—consult your pediatric gastroenterologist.

Cow's Milk Protein Intolerance (CMPI)

CMPI is the most common food allergy/intolerance in the first year of life. It differs from lactose intolerance because it involves proteins (not lactose) and can have both IgE-mediated (true allergy) and non-IgE-mediated (intolerance) components. The non-IgE-mediated form presents with: blood in stools, severe colic, persistent reflux, eczema. Diagnosis requires pediatric evaluation; management involves eliminating cow's milk (with hydrolyzed formula or soy-based formula if bottle-fed, or maternal dietary elimination if breastfed).

Signs That Suggest Intolerance in a Child

Signs that warrant evaluation: recurrent abdominal pain (more than three episodes per month for more than three months) with no obvious organic cause, chronic diarrhea or persistent loose stools, frequent abdominal bloating, slowed growth or unintentional weight loss, unexplained persistent fatigue, eczema that worsens in connection with certain foods. These are not signs of intolerance: crying, tantrums, sleep difficulties, hyperactivity (these attributions are often unscientific).

The Correct Diagnostic Path for Food Intolerances in Children

Step 1: Keep a food-symptom diary for 2 weeks (note everything your child eats and any symptoms with times). Step 2: Pediatric evaluation with the diary. Step 3: Specific tests as indicated (anti-tTG antibodies for celiac disease, skin prick test for allergies, breath test for lactose, possible RAST). Step 4: Elimination test only as recommended by a specialist and under nutritional supervision. Don't skip steps: elimination testing without diagnosis leads to unnecessary restrictive diets that can cause nutritional deficiencies in a growing child.

How to Keep a Food-Symptom Diary for Your Child

For 14 days: each day note breakfast, lunch, dinner, and snacks (main ingredients). Record the time and description of each symptom (pain: location, intensity on a 1–10 scale, duration; stools: consistency, frequency, presence of blood or mucus; bloating: when it appears relative to meals). Your pediatrician will look for temporal correlations: symptoms that appear consistently 30–120 minutes after certain foods (intolerance), or consistently 15–30 minutes after certain foods (allergy). This diary provides more information in 15 minutes of consultation than a week of generic tests would.

What to Do While Waiting for Diagnosis

Don't eliminate foods before completing diagnostic tests for celiac disease and allergies—both require that your child be consuming the suspected food for valid results. Don't give supplements or probiotics without medical guidance: some can interfere with testing. Keep your child on a varied, normal diet while you wait. Document every symptom in your diary. Consult your pediatrician if symptoms include weight loss, blood in stools, or slowed growth—these require urgent evaluation.