According to Jeanette Bradley for About.com, signs and symptoms of an apple allergy include tingling and itchy lips, a swelling tongue or throat, stomach cramps, diarrhea and rashes. In severe cases, anaphylaxis can result from the allergy.
Mayo Clinic explains that anaphylaxis is a life-threatening allergic reaction that can result in a coma or death if left untreated. Anaphylaxis causes airways to constrict and close up. This makes it difficult to swallow and breathe. Blood pressure drops and the heart rate increases. Finally, the victim suffers from lightheadedness and dizziness.
Bradley states that people with pollen allergies often show signs of an apple allergy because apples contain the same proteins. The allergic reactions are strongest when people consume fresh fruits and vegetables. Those who notice symptoms need to cook the apples first before eating them. If the allergy is cross-reactive, this should prevent the symptoms. Those who have an allergic reaction to apples and birch pollen need to be cautious when eating raw carrots, celery, hazelnuts, peaches, pears and potatoes.
To treat an apple allergy, Bradley suggests purchasing an over-the-counter antihistamine. If there are severe symptoms and anaphylaxis is a possibility, consult a physician or allergist for an epinephrine prescription.