Food intolerance is when your body struggles to digest food or a component of food, and this causes uncomfortable or unpleasant physical symptoms. It is different from an allergy and is not life-threatening like an allergy can be. Some of the most common culprits are dairy (specifically lactose), wheat or gluten, and caffeine. The most common symptoms of food intolerance are stomach pain, bloating, excessive wind, and diarrhoea. In some instances, food intolerances can lead to mild skin symptoms such as rashes or itching but these differ in severity from allergic reactions. If you were to suffer symptoms of an allergic reaction, not an intolerance, there is the potential for something called anaphylaxis to develop, which is life-threatening and can develop quickly. The symptoms may include coughing, wheezing, or have noisy or fast breathing. You may see the face, lips and tongue swelling, but the risk is if the throat swells, blocking the airways. Food intolerance symptoms are not very specific to food intolerance and commonly can be caused by other conditions such as stress, anxiety, irritable bowel syndrome, inflammatory bowel disease, and food allergies.
If you think you have a food intolerance you should book a routine doctor's appointment and in the meantime keep a food and symptom diary as this can help your doctor understand the symptoms and identify possible causes. You can also try cutting out what you think is causing the intolerance to see if your symptoms improve. Any signs of anaphylaxis or severe allergic reaction, with sudden onset swelling of the tongue or lips leading to breathing difficulties, should be treated as an emergency, you should call 999 for an ambulance.
The doctor will ask you about your current symptoms, your past medical history, and any relevant family medical history. Depending on your symptoms they may examine your skin or have a feel of your abdomen. In some cases, the doctor may do some tests such as a breath test (used sometimes to diagnose lactose intolerance) or blood tests.