A food allergy is an immune system reaction to a particular food. Reactions can be mild, but they can also become severe. Food allergy is different from food intolerance, which does not involve the same allergic immune response.
Symptoms
- Itching, hives or flushed skin
- Swelling of the lips, face or eyes
- Coughing, wheezing, breathlessness or a hoarse voice
- Nausea, vomiting, abdominal pain or diarrhea
- Dizziness or feeling faint
Symptoms often begin within minutes, although some food-related allergic reactions can be delayed. The timing and pattern depend on the type of allergy.
When to Get Emergency Help
Contact your local emergency services immediately for swelling of the tongue or throat, difficulty breathing, collapse, severe dizziness or loss of consciousness. Use a prescribed epinephrine auto-injector immediately according to the person’s emergency plan and device instructions.
Diagnosis
A healthcare professional will ask what was eaten, when symptoms began and whether similar reactions have happened before. Assessment may include skin prick testing, specific IgE blood tests or a medically supervised food challenge. Commercial home allergy tests are not a reliable substitute for clinical assessment.
Management
Avoid confirmed trigger foods, read ingredient labels and tell restaurants, schools and caregivers about the allergy. People at risk of anaphylaxis may be prescribed epinephrine auto-injectors and should keep them available as instructed. A registered dietitian can help prevent nutritional deficiencies when important foods must be excluded.
Do not remove major foods from a child’s diet or attempt a food challenge at home without advice from a qualified healthcare professional.
Related topics
Sources and Further Reading
Last reviewed: 4 September 2026. This page provides general health information and does not replace individual medical assessment or treatment.