While many of us often think of acne as a teenage affliction caused by raging hormones, there are lots of other things that can cause acne, and acne can affect people of all ages. One little-known cause of acne is food allergy. Swelling and inflammation of the skin is one of the symptoms of allergies; acne is simply another kind of inflammation.
If you notice acne appearing after you eat a particular food, you may have a food allergy. Other, more common food allergy symptoms include swelling, hives, difficulty breathing, abdominal pain, nausea, vomiting and diarrhea.
If you suspect a food allergy, see an allergist for a diagnosis. He may do a skin prick test, applying a small amount of the allergen to a scratch on the skin of your arm or back and watching for a reaction. He may also do an Immunoglobulin E (IgE) test to check for antibodies in your blood. Your doctor may prescribe medication to treat your systems but the best treatment for allergies is to stay away from the foods you're allergic to. If you have a severe allergy your doctor may give you epinephrine to keep with you in case you have an anaphylactic (life-threatening) reaction.
Food intolerances, which are gastrointestinal reactions, can also cause skin problems, but these cannot be detected by IgE or skin prick tests. If your tests come up negative for food allergies, your doctor may perform other tests to check whether you have food intolerance, or he may instruct you to do an elimination diet. In this case you will eliminate the suspected allergens from your diet for a specified period of time and then reintroduce them one at a time. When the acne and other symptoms return, you will know which food is causing them. In the case of food intolerance, there is no treatment and you will have to abstain from eating the offending foods in order to stay symptom-free.