Food allergies are reactions by the immune system to certain foods. Most food allergies are diagnosed in children, but it is possible for adults to develop food allergies. Children who have food allergies sometimes outgrow the allergy. Adults who have food allergies will typically have the allergy for the rest of their lives.
Food allergies seem to have a regional component since the foods people are usually allergic to are those foods they eat often. So for example, rice allergy is more common in Japan while codfish allergy is more common in Scandinavia.
In order to diagnose a food allergy, the doctor must first rule out other health problems that can cause similar symptoms. An allergist or immunologist is a doctor who specializes in caring for patients who have allergies. Your allergist will probably use a variety of tests to determine whether you have a food allergy and what you are allergic to.
• History – A basic physical examination and asking questions about your health can help your doctor find out about your symptoms and what is normal for you. Your doctor will probably ask questions about your symptoms including when they started, what symptoms you notice and what food you believe might be a trigger for your symptoms. Timing of your reaction is important, so try to remember how long it took after you ate before you experienced symptoms and how bad the symptoms were. Also think about how the food was prepared. For example, do you always react to fish or only to undercooked or raw fish?
• Diet Diary – If you can’t remember exactly what you ate or how quickly symptoms occurred, your doctor may ask you to keep a diary of what you eat. It is important to record everything you eat in your diary, not just the foods you believe are problematic.
• Elimination Diet – This tool can help your doctor figure out exactly what foods you are allergic to. The diet starts with food choices that are generally considered “safe” because few if any people are allergic to them.