The reason why some people are affected by allergies while others are not begins in their genes.
The Allergic Reaction
According to the American Academy of Allergy, Asthma & Immunology (AAAAI), there are about 50 million people in the U.S. who suffer from some type of allergy. Allergies are related to your immune system, the body's system that provides defenses against diseases and other threats. When you are allergic to a certain food, your body interprets this as a danger to you, and whatever you are allergic to is called an allergen. The body then responds by producing antibodies that are called Immunoglobulin E (IgE). An allergic reaction occurs when these antibodies release chemicals that cause a variety of allergic reactions.
When your body realizes that an allergen has entered your system, it begins one of several processes to rid the body of the allergen. A peanut allergy reaction can develop only minutes after eating the substance, or up to two hours later. You may develop a runny nose, sneezing, itching around the mouth, or in the mouth. These are all your body's way of trying to eject the substance from your body.
Severe Allergic Reactions
If you develop diarrhea or vomiting after eating a certain food that you are allergic to, your body is attempting to force the allergen out of your system. Some people develop stomach pain and cramps. The skin also attempts to rid the body of the allergen that is causing the problem by reacting by forming hives or a rash. If you or your child were fine before eating the foods listed above, but any of the allergic reactions mentioned occur after eating these items, this is probably an indication of a food allergy. A life-threatening conditioned called anaphylaxis can quickly develop, so it is important to get emergency medical treatment if a person is having trouble breathing or is having a whole-body allergic response.
Stopping an Allergic Response
A mild allergic response will simply go away on its own in most cases. If a child develops a rash but has no other symptoms, a dose of antihistamine may be all that is required. Let your pediatrician know that your child had this response after eating a certain food. More serious allergic responses usually require a fast trip to the doctor's office or emergency room where ephinephrine is injected to stop the allergic response. People with serious allergies then need to carry this drug with them at all times in case they accidentally eat a food that could cause anaphylaxis again.