Food reactions are real—but the label matters
Patients often know that a meal makes them feel worse. The difficult part is identifying why. An immediate food allergy, celiac disease, lactose intolerance, fermentable carbohydrate sensitivity, reflux trigger, and coincidence require different evaluations.
I take the symptom seriously without assuming that one broad panel can identify every problem food.
Allergy, intolerance, and sensitivity
Food allergy
A true food allergy involves the immune system and can cause hives, swelling, wheezing, vomiting, or anaphylaxis. Evaluation should be guided by a detailed reaction history and, when appropriate, an allergy specialist. Skin or food-specific IgE tests can support the evaluation, but a positive test alone does not always prove clinical allergy.
Food intolerance
An intolerance usually involves digestion or dose-dependent symptoms rather than a dangerous allergic response. Lactose intolerance is a common example. Symptoms may include gas, bloating, pain, or diarrhea.
Food-specific IgG panels
Major allergy organizations recommend against using food-specific IgG or IgG4 panels to diagnose food allergy or intolerance. IgG commonly reflects exposure to a food and may be associated with tolerance. Broad panels can lead to unnecessary restriction, cost, anxiety, and nutritional gaps.
A safer way to investigate food-related symptoms
- Build a timeline. Record the food, amount, timing, symptoms, medication use, and other possible triggers.
- Rule out conditions that need testing first. Celiac testing, for example, can become less reliable after gluten has already been removed.
- Use a focused elimination only when appropriate. Remove the smallest reasonable group of foods for a defined period.
- Reintroduce systematically. Reintroduction helps determine whether the suspected food actually reproduces symptoms.
- Protect nutrition. Multiple exclusions may require a registered dietitian, especially for children, pregnancy, low weight, or a history of disordered eating.
When to seek urgent care
Difficulty breathing, throat tightness, faintness, rapidly spreading hives, or swelling after food can be an emergency. Follow your allergy action plan and seek emergency care rather than trying an elimination diet at home.