Food allergy is relatively common in young children, with milk or egg allergy often associated with eczema. In adults type 1 food allergy is most often to nuts or peanuts or fish.
Severe type 1 reactions can occur in patients with IgE to foods: particularly to 
nuts. These can cause swelling of the mouth and throat, generalised itching and swelling (oedema), difficulty breathing (due to throat swelling or asthma) and a fall in blood pressure leading to collapse. Such reactions . must be investigated thoroughly and patients must be advised on appropriate food avoidance and carrying an injectable syringe of epinephrine (Epipen, ALK or similar) which reversed some of the effects of anaphylaxis. Such patients should have clear management plan, may carry a warning bracelet or necklace (such as Medic-Alert) and can gain useful information from the Anaphylaxis Society. Food anaphylaxis can occur to many foods types (including sesame seed, specific mils, fruits etc) and requires careful history and investigation with skin or blood tests.
Other food reactions may be less severe. These include cross reactions between allergen in foods and other allergens to which the patient is sensitised. Examples are itching in the mouth due on eating apples, pears or other fruits due to birch pollen allergy, or reactions to kiwi, avocado or banana due to latex allergy. These symptoms can generally be managed by avoidance and anti-histamines.
Food Intolerance
There is a wide variety of symptoms associated with foods that do not result from IgE to the food. These tend to be more variable (they don’t always occur when the food is eaten), more dose related (often only occurring when large quantities are ingested) and generally cause gut symptoms (typically bloating or diarrhoea). These symptoms should be investigated, malabsorption ruled out and often avoidance is helpful.
IT IS IMPORTANT TO MAKE SURE THAT AVOIDANCE DIETS REMAIN BALANCED and dietetic help is invaluable.