Allergies stem from an inappropriate reaction of the immune system to certain proteins. These proteins are known as allergens, and they are usually common and harmless substances such as pollen, mold spores, animal dander, dust, various foods, insect venoms, or medicines.

Any substance that triggers an allergic reaction is called an allergen. There are many different types of allergens; three of the most common are pollen, dust mites and nuts. Allergens contain protein, which is found in all living organisms, and it is the protein that causes the reaction. Some drugs such as penicillin can also cause allergic reactions. They do not contain protein, but they can cause a reaction if they bind to proteins in the body.

Cause Of Allergy

An allergic reaction occurs when the body's immune system overreacts to an allergen, in this case a food protein.
•The white blood cells produce an antibody to this allergen, called immunoglobulin E or IgE.
•Any food has the potential to trigger an allergic reaction, but a few foods account for most food allergies.

Allergic reactions occur when the immune system misidentifies harmless foreign substances and reacts to them as if they were as harmful. These substances are called allergens. Common pollens, mold spores, house dust mites, cockroaches, and animal dander (shed skin, fur, or feathers) are among the allergens that most frequently cause problems. Allergic reactions to allergens such as insect venom, latex, and certain types of food or medications are more rare.

Symptoms Of Food Allergy

Reactions to foods are usually rapid, appearing within an hour (or sometimes even seconds) of consumption, although in some cases they may be delayed and appear up to four hours after eating.

Skin rashes, such as nettle rash (also called urticaria or hives) can appear which are generally short lived, disappearing within a few days. Longer lasting, chronic skin reactions (such as scaly patches) can also be experienced. Some of these longer lasting rashes are called atopic dermatitis.

The complex process of digestion affects the timing, location, and particular symptoms of an allergic reaction to food. All of the symptoms of food allergy occur within a few minutes to an hour of eating. A food allergy can initially be experienced as an itching in the mouth and difficulty swallowing and breathing. Then, during digestion of the food in the stomach and intestines, symptoms such as nausea, vomiting, diarrhea, and abdominal pain can start

You may also get some or all of the following symptoms:
• skin reactions, such as swelling and itching, eczema and flushing
• vomiting and/or diarrhoea
• coughing, wheezing or a runny nose
• swelling of the lips
• sore, red and itchy eyes

Home Treatment

• For localized hives or other mild skin reactions
• Take cool showers or apply cool compresses.
• Wear light clothing that doesn't irritate your skin.
• Take it easy. Keep your activity level low.
• To relieve the itching, apply calamine lotion or take over-the-counter antihistamines, such as diphenhydramine (Benadryl) or the nonsedating antihistamine, loratadine (Claritin).