The most common symptoms of food allergies are nausea, vomiting, diarrhea, constipation, headaches, rashes, shortness of breath, and some times swelling. The good thing is that it a food allergy generally produces the same symptoms each time. The exception to this would be a peanut allergy, which can become more severe each time the person is exposed.

Allergies actually develop in stages. When a person first encounters the substance that it is allergic to there is most often not a reaction. The body wards to fight this off. When the body is exposed again, symptoms will be produced. The more the body is exposed to the allergen, the more likely a reaction will occur. These can be a simple as sneezing, watery eyes, and runny nose. Some can be a serious as sudden death.It is possible that some people can handle small amounts of the foods, which they are allergic to without much difficulty. While others are so sensitive that they react to even the smallest traces. Most reactions are fast, usually within a few minutes of the food entering the body and can occur up to two hours later. In some cases the reaction does not occur for up to forty-eight hours later. These are the ones that are difficult to identify.

Some allergens are easy to identify because the reaction is immediate. In other cases you may be asked to keep a diary of what you ate and the times. After a while a pattern will begin to show what the problem foods are. In some cases allergy testing may need to be done. The most common are the skin test where food allergens are placed on the skin and swelling or itching will occur if you have a reaction. In other cases the doctor may order a (RAST) radioallergosorbent blood study. This test allows for a few drops of a person’s blood to be mixed with the allergens and then analyzed for signs of a reaction.

In one such test known as double blind challenge or provocation test, opaque capsules containing the suspected substance are alternated randomly with a non-active substance and eaten with the elimination diet. If the person always responds to the presence of substance, even when he is unaware of it, with asthma, eczema, allergic rhinitis hives or other physical reactions, the possibility of his having a true allergy or physiological intolerance is strengthened. If a person taking the double blind challenge doesn’t always respond, or develop only less clear cut symptoms, such as nausea, headache, behavioral problems and general discomfort, psychological causes of intolerance will be suspected. So, the best thing is to detect the food allergens and eliminate them from the diet.

The simple procedure to detect the food allergen is to put the individual on a very simple elimination diet, which consists of a few basic foods that are almost never associated with food allergies or intolerance. Symptoms are monitored for several weeks, and foods are gradually added back to the diet. If symptoms then occur, more sophisticated tests are used to determine which kind of problem is present.

Allergists sometimes inject a suspected allergen (allergy causing substance) under the skin. If the person has an allergy, a skin irritation will develop at the location of the injection. Another test, the cytotoxic test, in which the suspected food is placed with white blood cells from the patient, is not used by reputable specialists.

Once the allergens have been identified and eliminated from the diet the problem should be solved. This can sometimes be more difficult that it sounds. Some of the more common food allergens are hard to avoid.