Typical symptoms of a food allergy reaction include:   * itchy or scratchy throat * abdominal pain * diarrhea * nausea * vomiting * stomach cramps * itching of the mouth, throat, eyes, skin, or any area * hives * runny nose * shortness of breath * wheezing * difficulty swallowing   The trouble is, cramps, diarrhea and vomitting may also be signs of a food intolerance (which is different from an allergy) or some other condition. But you must be extremely careful feeding your son peanuts or any other product containing peanuts if you suspect and allergy. You don't want him to go into anaphylaxis, a severe, systemic allergic reaction that happens suddenly. Typical symptoms include swelling in the throat, constriction of the airways resulting in wheezing, difficulty breathing, abdominal pain, cramps, vomiting, and diarrhea and/or hives on the lips, the face or elsewhere on the body. Anaphylaxis, if not treated properly right away, can be deadly.   If you're very concerned talk to your doctor. A walk through your son's medical history may help the doctor better understand if the trouble is truly from a food allergy. Some tests that may help determine what food your son may be allergic to (if any) include:   * Food elimination diets -- the suspected food is eliminated from the diet until the symptoms disappear, then reintroduced to see if allergic reaction develops. This method is not foolproof but may be used to narrow the list of suspected foods. * Food provocation diet. * Skin tests. * RAST test -- blood tests for antibodies to a specific allergen.