Food allergy is an immune system response to a food protein that occurs soon after eating an allergy provoking food. The process of digestion is very complex and it affects on the specific symptoms of an allergic reaction to food.

The symptoms of food allergy begin to appear within a few minute after eating the food. But the reaction of these symptoms usually takes 1 to 2 hours to occur.
An estimated ratio of food allergy among children of under age 3 is about 6 to 8 percent while 4 percent of adults suffering from this allergy.

Mostly food allergy mix with food intolerance that is a less serious condition and it does not involve the immune system.The symptoms of a food allergy can be mild, severe or even life-threatening.  The most common symptoms are categorized as Skin, digestive, respiratory and anaphylaxis reactions.

Symptoms included in these reactions are following:
Skin symptoms like hives (urticaria), itchy, scaly rash called eczema (or atopic dermatitis) occurs when the absorbed allergy enter in the bloodstream and then in the skin. It also cause of redness or flushing (erythema) and swelling (edema) on the lips and mouth.

Digestive system, the symptoms such as abdominal pain, nausea, stomach cramps, vomiting and diarrhea can start when food reach to stomach and intestines. These symptoms sometimes mix with various types of food intolerance.Respiratory symptoms are sneezing, coughing, stuffy nose, wheezing, scratchy throat and breathing difficulties, asthma, watery eyes and Tightness in the chest appear in the reaction of food allergy. From the skin, allergens enter into the airways there they can cause of respiratory reactions.

Anaphylaxis:
Anaphylaxis can affect various parts of the body including the skin and the digestive and respiratory systems or sometime it just covers respiratory or cardiovascular symptoms. Anaphylaxis is a sudden drop in blood pressure occurs when the allergens travel through the blood vessels. It generally begins within 5 to 60 minutes after the exposure and they

starts with mild symptoms including:
- loss of consciousness
- tingling in the mouth
- falling blood pressure
- light-headedness
- difficulty in breathing
- dizziness
- Rapid or irregular heart beat
- including difficulty breathing
- swelling of the upper throat

Anaphylaxis can be fatal and cause a coma or death. Each year, about 150 people in the United States die of food-related anaphylaxis.

People who are suffering from severe allergic reaction need to take special precautions and avoid such food that cause allergy.