If you develop swollen lips after eating raw almonds, you may have oral allergy syndrome, also known as OAS, an allergic reaction that occurs as a cross-reaction to another substance, in this case, birch tree pollen. You may also develop swollen lips if you have a tree nut allergy. Almonds are considered tree nuts although they actually belong to the Rosaceae family, which includes a number of fruits. If you develop swollen lips while eating raw almonds, stop eating them immediately and notify your medical practitioner.
Oral allergy syndrome develops when you have an allergy to a substance such as birch tree pollen. In 25 percent of cases, people who develop OAS reactions to peaches may also react to almonds, according to Food-Info, a website associated with Wageningen University in The Netherlands. Similar proteins in raw almonds can also trigger an allergic reaction. Allergies to raw almonds themselves occur less frequently than other nut allergies. Allergies happen when your body develops antibodies to a substance. The body releases histamines in response to the allergic reaction; histamines produce the allergy symptoms. Allergic reactions often worsen each time you come in contact with a substance.
In addition to swollen lips, oral allergy syndrome can cause tingling in the mouth or lips, itching in the lips or throat, tongue swelling, sneezing and itchy, watery eyes. Severe reactions such as vomiting, diarrhea, abdominal pain, wheezing, difficulty breathing and circulatory collapse can occur in anaphylaxis. Just touching the nut may cause rash, itching or swelling of the skin.
For mild reactions, an oral antihistamine over-the-counter medication such as diphenhydramine may be enough to quell the histamine response. For severe reactions, an injection of epinephrine may be needed to reduce the histamine response.
If you have severe allergic reactions to raw almonds, always carry injectable epinephrine. Learn to read food labels carefully for sources of almonds in foods and avoid all tree nuts unless allergy testing has proven that you’re not allergic to them. In at least one case reported on Food-Info, curry ingestion triggered an almond allergic reaction. Some foods that trigger OAS cause a reaction only when eaten in raw form; heat-processed almonds may not cause a reaction, according to Food-Info, but do not try to eat them without your doctor’s approval. Dr. Anthony Ham Pong, M.B., recommends avoiding nuts completely, whether raw or cooked, in an article published in the June 2000 "Allergy and Asthma Information" newsletter.