Allergic reactions typically begin within minutes and disappear within hours after consuming the allergen, according to Foodallergens.info. Symptoms may also develop hours later and can last for days.
Symptoms of food allergy include intestinal symptoms, such as vomiting, diarrhea and nausea, and skin reactions such as rashes, states the Allergy, Asthma and Sinus Center. Other symptoms include asthma, blood pressure loss and swollen tongue, lips or throat. Individuals with a mild allergy may experience only sneezing or a runny nose, whereas those with severe allergy may suffer fatal reactions.
Food allergies occur due to the immune system’s reaction to food proteins known as allergens, explains the Allergy, Asthma and Sinus Center. The immune system of a nonallergic individual typically ignores allergens. In contrast, the immune system of an allergic person creates higher amounts of immunoglobulin E, or IgE, which is an antibody. The body releases histamine and other chemicals once the IgE antibodies merge with food allergens. The chemicals may lead to blood vessel dilation and muscle contraction.
Anyone who has a food allergy should post a list of food allergens, symptoms and recommended treatments in a conspicuous area in the kitchen, says the Allergy, Asthma and Sinus Center. Those with severe allergies should learn how to handle proper treatment using an injectable device in case of a serious allergic reaction.