A range of factors can cause bad reactions to food, from allergy to intolerance or enzyme deficiencies.

Food allergy

Allergies to peanuts, tree nuts (such as almonds and cashews), fish and shellfish can be lifelong. These are also the most common foods to cause life-threatening anaphylaxis, the severest allergic reaction. Allergic reactions can vary in severity, and can range from skin swelling, rashes and stomach upsets to low blood pressure and difficulty breathing.

Food allergies are an uncommon trigger for asthma. Despite what many people think, cow’s milk and other dairy foods rarely trigger asthma symptoms in people without milk allergy.

Food sensitivities

Food intolerances and enzyme deficiencies (when your body cannot process certain substances) are sometimes mistaken for food allergies. In general, these reactions tend to cause headache, bloating and stomach upset, and are less severe than allergic reactions. They do not cause anaphylaxis.

These food sensitivities include lactose intolerance, gluten intolerance (coeliac disease), and sensitivity to some artificial colours, flavours and preservatives.

What to do

Your doctor can help you identify the cause of your food reaction, to find out if you have an allergy or sensitivity. Once the culprit is identified, you should avoid those foods known to cause a reaction.

For some people with intolerance or sensitivities, small amounts may be OK or cause only mild discomfort. However, for some people with allergies, even the slightest exposure may cause serious or life-threatening problems.

Information adapted in part from Patient Information: Adverse Reactions to Food, Australasian Society of Clinical Immunology and Allergy

Want to know more?

If you would like to view copies of our useful guides, find out more information on managing your conditions or get tips on how to avoid common asthma and allergy triggers, please go to Living with Asthma & Allergy.

Medical Disclaimer
Although all care has been taken, these publications are a general guide only and are not intended to be a substitute for individual medical advice or treatment. Any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner. The National Asthma Council Australia expressly disclaims all responsibility (including for negligence) for any loss, damage or personal injury resulting from reliance on the information contained herein.

Content Updated 20 December 2009