What are the symptoms of food allergy and food intolerance?

Food allergy and intolerance symptoms differ. The symptoms of a food allergy tend to be relatively predictable, and include the following:

  • Hives/welts: These skin reactions happen in about 90 percent of patients with an allergy. Hives tend to be itchy welts with individual lesions lasting more than 24 hours, although the total rash itself might come and go over more than a day. If you break out in a rash, take pictures to show your healthcare professional.
  • Swelling (angioedema): There may also be swelling of the mouth, face, hands, feet or groin area.
  • You may experience abdominal pain, nausea, vomiting or loose stools.
  • You might get lightheaded, or feel dizzy or about to pass out.
  • Anaphylaxis: Allergic reactions also carry with them the risk of death.

Since a food intolerance is caused by many different factors, the symptoms are less predictable. One of the keys to diagnosing food intolerance is to make sure it’s not an allergy. If none of the above food allergy symptoms sound like your symptoms, then you more likely have a food intolerance. Typical symptoms might include one or more of the following:

  • Rash: not a hive rash, but a red rash that may or may not be itchy and tends to last for more than 24 hours.
  • There is rarely swelling.
  • There is often abdominal pain, nausea, possibly vomiting, constipation or loose stools. This is a very common symptom with food intolerance.
  • Headaches sometimes happen. But feeling lightheaded, dizzy or passing out is very unusual for a food intolerance.
  • You may feel fatigued or have decreased energy.
  • Weight gain or weight loss is not a usual symptom of intolerance although it can happen. It is always important to search for more common causes of weight changes if this is the only problem.

An intolerance should not kill you. It might make you feel miserable, but only a food allergy has the risk of death.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.