Food Sensitivity Concerns
Food sensitivity (intolerance) differs from true food allergy: intolerance does not involve the immune system in the way an IgE-mediated allergy does, per the NIAID-sponsored 2010 Guidelines for the Diagnosis and Management of Food Allergy.
Symptoms
Food intolerance typically causes digestive symptoms (bloating, gas, diarrhea, stomach pain) hours after eating a trigger food, without the hives, swelling, or breathing difficulty that mark a true allergic reaction.
Causes and risk
Enzyme deficiencies (like lactase for dairy), sensitivity to certain carbohydrates (FODMAPs), or reactions to food additives are common causes of intolerance, distinct from the immune-mediated mechanism of true allergy.
How it is evaluated
Food-specific IgG/IgG4 testing is not recommended by the American Academy of Allergy, Asthma & Immunology (AAAAI) or the NIAID expert panel, since IgG antibodies to food reflect normal exposure rather than disease. A supervised elimination diet remains the most reliable way to identify a trigger.
Treatment
A structured elimination diet -- removing a suspected trigger for a defined period, then reintroducing it systematically -- is the standard approach, per AGA technical review guidance. Celiac disease should be ruled out with blood testing before gluten is removed from the diet, since removing gluten first can make celiac testing inaccurate.
When to seek care
Hives, swelling of the lips or throat, difficulty breathing, or dizziness after eating are signs of a true allergic reaction or anaphylaxis -- this is a medical emergency. Use an epinephrine auto-injector if available and call 911 immediately.