Allergic reactions vary a lot and can begin immediately after you eat the food or start several hours later. The symptoms below are typical of food allergy: swollen lips, face or throat; itchy sensation in the mouth and lips; vomiting, stomach cramp and diarrhoea; headache, fatigue and irritability, hay fever, asthma; rash, nettle rash and pre-existing eczema may get worse.
Once you have become sensitised to a food, your immune system produces more antibodies every time you eat that food. This means symptoms that are mild one day can be serious the next. If you have a food allergy, you should never put yourself at risk of a reaction to make life easier when eating out or at other people’s houses. In rare cases, eating even a tiny amount of the food can cause anaphylactic shock. This is a life-threatening reaction by the immune system that causes the airways to narrow and heart to malfunction. It needs immediate treatment with adrenaline.