A food allergy is an abnormal response to a food triggered by your body's immune system, but a food intolerance is different to an allergy.
It is common to have a reaction to a certain food, but in most cases it’s an intolerance rather than a true allergy. Although they may have similar symptoms, a food allergy can be more serious – it is very important to know the difference.
Food intolerance:
- Usually comes on gradually over years
- Discomfort or effect may only happen when you eat a lot of the food
- The effect may only occur if you eat the food often
- Is not life-threatening
Food allergy:
- Symptoms usually come on suddenly
- A small amount of food can trigger the reaction
- Symptoms occur every time you eat the food
- The reaction can be life-threatening
In adults, the foods that most often trigger allergic reactions include fish, shellfish, peanuts, and tree nuts, such as walnuts. Problem foods for children can include eggs, milk, peanuts, tree nuts, soy, and wheat.
Shared symptoms for allergy and intolerance:
- Nausea
- Stomach pain
- Diarrhoea
- Vomiting
Symptoms of food intolerance
Intolerance can mean that a food irritates your stomach or your body can't properly digest it – you may have these symptoms:
- Gas, cramps, or bloating, constipation or diarrhoea
- Heartburn
- Headaches, migraines
- Irritability or nervousness, tension
- Sinusitis, rhinitis, wheezing
- Eczema, rashes, hives
- Chronic fatigue syndrome, fibromylagia
Symptoms of food allergy
- Symptoms are similar to those of an intolerance but to a much greater degree, leading to life- threatening levels without intervention
- Itching or swelling in your mouth
- Tightening of the throat and trouble breathing
- Anaphylaxis
- Itchy eyes leading to swelling of the eyelids
- Vomiting, diarrhoea, or abdominal cramps and pain
- Hives or eczema
- Drop in blood pressure
Diagnosis
Your doctor can use a detailed history, elimination diet, and skin and blood tests to diagnose a food allergy. They can also help you find out if you have an allergy or intolerance. You may need to keep a diary of the foods you eat and the symptoms you have and during the programme eliminate some foods to find out which one is causing symptoms.
Treatment
If you have a food allergy, you'll need to stop eating the food altogether. If you have a food intolerance, you’ll need to avoid or cut back on that food in your diet, depending on the severity of your symptoms. For example with lactose intolerance, you can look for lactose-free milk or take a lactase enzyme supplement.
With a food allergy, you could be at risk for anaphylaxis, a life-threatening reaction. Ask your doctor if you need to carry an Auvi-Q or Epi-Pen (adrenalin shot) that you could give yourself in an emergency. You can also make use of a medic-alert device in case of emergencies.
