Egg allergy is a rare occurrence in adults. The allergy is common in young children, and it is usually outgrown, according to the National Institute of Allergy and Infectious Diseases. Egg allergy is difficult to diagnose because it is a common ingredient in many foods, and in some cases the food labels do not carry the name "eggs" on the list. The Nemours Foundation has a list of food with egg as common or hidden ingredient that can help with an egg-free diet.
Hives and eczema are the most common allergic reactions to egg. Hives, or urticaria, are tiny red rashes that form anywhere on your body, within minutes to hours after ingesting egg or food with egg ingredients. Hives usually resolve within 24 hours after exposure. If you have an egg allergy you may also experience swelling of your lips, eyelids, tongue or throat on eating food containing egg.
In adults with egg allergy, eczema first appears as itchy rashes in the bend of your elbow, back of your knees, ankles and wrists, neck, face and palms of your hands and soles of your feet. In time, the rashes become dry, thick and brownish in color, and fluid may ooze out of your affected areas. Eczema may require an antihistamine to relieve your itchiness and soothe your scaly rashes.
Adults with egg allergies may experience a variety of respiratory symptoms, including hay fever and asthma upon breathing powdered egg ingredients. Nasal symptoms may include itchy, watery eyes, runny or stuffy nose, and headache or sinus pressure. You may also experience wheezing, coughing, difficulty breathing and other asthma symptoms. Asthma may require immediate intervention because mild symptoms of wheezing can quickly progress to severe breathlessness.
Egg can cause a life-threatening allergic reaction called anaphylaxis. Anaphylactic shock occurs when several systems or areas of your body simultaneously react on exposure to egg. If you have an egg allergy you may experience difficulty breathing and chest tightness as your tongue, throat or airways swell and constrict. Other symptoms include belly cramps, diarrhea, nausea or vomiting as your body attempts to get rid of the egg inside your digestive tract. Rapid pulse, severe drop in blood pressure and fainting are severe symptoms of anaphylactic shock. Anaphylaxis develops suddenly and requires immediate medical attention.
Even when adults have egg allergy, the disorder usually begins in childhood or early adulthood. It is rare to see adult-onset egg allergy, such as a case presented in a 2007 study in the Journal of Investigative Allergology and Clinical Immunology of a female patient developing egg allergies in her 50s.