This is an immune system reaction to food. And the reaction usually occurs quickly after eating the food. Sometimes within seconds. The symptoms can be mild or severe, even life-threatening in some cases. The most severe form of reaction is the anaphylactic reaction.
An allergy can occur to any food. But it would most likely be to one of these foods: milk, eggs, nuts, peanuts, fruits, wheat, soya and fish or shellfish.
Food allergy symptoms include:
- tingling or itching or swelling in the mouth or throat
- difficulty swallowing or wheezing
- an itchy red rash
- sneezing or itchy eyes
- feeling dizzy or nauseous
- abdominal pain or diarrhoea
An anaphylactic reaction might begin with the symptoms above but can become more serious. With increased breathing difficulty, a rapid heartbeat, sudden drop in blood pressure and unconsciousness.
Skin prick tests, or blood tests for specific IgE antibodies can diagnose food allergy.
People with food allergy are susceptible to future reactions. They need to avoid their trigger foods completely. After an anaphylactic reaction it is best to carry an EpiPen or similar. These allow someone to self inject adrenaline in an emergency.
The symptoms of food intolerance are much more diverse and are not a medical emergency. They are also likely to happen much longer after eating the food. Sometimes hours or days later. Symptoms can be vague and may not be a associated with the food that caused them. And, the person may tolerate a small amount of the food but if they eat a larger portion they can develop symptoms.
The most common symptoms of food intolerance are gut symptoms. Including, bloating, diarrhoea, constipation, skin problems and joint pain. Others might include brain fog, lethargy, headaches or migraine, or generally feeling unwell.
Causes of food intolerance include not being able to properly digest food. Or a reaction to something contained in food.
People with suspected food intolerance should keep a diary of foods eaten and symptoms. Elimination of suspected foods, and later adding them back can identify intolerances. This can be a long and pains taking process. So, many people opt for a food intolerance test to speed up the process.