IgE levels are measured in the blood test, higher level than normal indicate allergy. A blood test to explore causes of food allergies is called RAST. Skin prick tests are also carried out, using the protein in the food, in very , very small amounts pricked in to skin.
Allergic reactions happen when a food protein enters the blood stream, by eating or rubbing in to eye, or in the case of hay fever, when breathed in for instance. The body mistakes the protien as an illness or virus and the mast cells that attack an infection , realease histamine. Histamine has nothing to fight, and causes two main serious effects on the body.
It causes the small blood vessels to dilate and loose blood, and produces symptoms like lowering blood pressure, dizzyness, feeling faint, and is a serious symptom.
It also causes smooth thick muscles to narrow and contract, and this can cause the small tubes in lungs to narrow (asthma) or cause the muscles in throat to narrow, constrict or block.
Other visable symptoms are the hives, the swelling and vomiting and loose bowel.
understanding these symptoms and how to treat them is important, the anaphylaxis campaign can help with this , please ring their help line. I have , many times over the years!
Milk allergic children used to be given soya formula milk, but this was found to be not recommended. As soya is a legume, like peanuts and can cause more problems within this food group, also other problems found in soya milk were proved to be unhealthy, but i cant quite remember why, sorry.
Now infants with IgE response food allergies are given formula that has totally changed protein strands, such as neocate and others.
Treatment for those having anaphylaxis is normally an epi pen or ana pen, whcih give a small dose of adrenaline which given early enough works well. If epi pen is required, hospital visit is needed every time. A epi pen is not a cure, and sometimes reaction can start again, so hospital need to check lung function, blood pressure etc, and give oral or drip steriods to control the reaction. after discharge from hosptial these steriods are continued for some days afterwards to prevent reaction from returning.
a good book to buy is 'the complete guide to food allergy and intolerence' by proff j brostoff , published by Gamlin.
when you go back to this doc, take a list of questions with you and go through it one by one. good luck.