Diagnosing Food Allergy
The doctor will first take a careful history to determine what the offending food might be and whether the time between eating the food and the onset of symptoms suggests an allergic response. Possible investigations include skin prick tests, in which dilute solutions are made from foodstuffs. A drop of each solution is put on the skin, which is pricked with a needle; the skin is then monitored for a reaction. These tests are not always reliable because a significant number of people who test positive to a certain food will not have allergic symptoms when they eat it. However, negative results are more reliable and virtually rule out the possibility of allergy to the food tested.
In some cases of suspected food allergy, blood samples are taken and antibody levels to certain food proteins measured. Known as RAST tests, these investigations are less reliable than skin tests.
If a skin test or a RAST test for a particular food is positive and the diagnosis is backed up by the symptoms described, the food should be tested using a double-blind food challenge. In this test, responses are monitored to the food and to a placebo. These are presented in such a way that neither the patient nor the investigator knows which is which.
Diagnosing Food Intolerance
There is no specific group of tests to investigate food intolerance apart from testing for gluten and lactose intolerance. Often, the diagnosis is made from a description of the symptoms. However, in certain cases, such as lactose intolerance, specific tests may be appropriate.
Treatment for Food Allergy russian food store
The treatment aim for food allergies is to avoid the offending food. Antihistamines may be taken if the food is mistakenly ingested and severe swelling and shock (anaphylaxis) require medical urgent treatment with intravenous drugs. For this reason, people with known food allergies are given easy-to-use injectable doses of adrenaline (known as Epipens) to keep with them and use if the signs of an allergic reaction develop.
Food allergies and intolerances: why does it occur?
The symptoms of food allergies are caused by an abnormal or exaggerated immunological response to one or more proteins in a particular food. Various theories have been put forward to explain why food allergy develops in infancy rather than later in life. It has been suggested that babies have an immature immune system and that their stomachs produce less acidic juices, allowing more proteins to reach the small intestine and trigger allergic responses. The majority of food allergies tend to resolve in early childhood. However, some, such as peanut allergy, may be life-long.
Food allergy seems to be more common in children with other atopic conditions, such as asthma and eczema. Relatively few foods are responsible for the majority of allergic reactions. Common allergenic foods include cow’s milk, eggs, peanuts, tree nuts, fish and shellfish.
Food Intolerances may have a variety of causes, including a lack of certain chemicals in the body. One example of this is lactose intolerance. It is caused by insufficient amounts of the enzyme lactase, which is needed to break down the sugar lactose found in milk. Lactose intolerance is common in people of Afro-Caribbean, Asian and Mediterranean descent and it also seems that as people grow older they produce less lactase and therefore may be more likely to develop lactose intolerance.