For some people, an allergic reaction to certain kinds of food can be quite uncomfortable, but not necessarily severe. On the other hand, for certain people, the allergic reaction to a certain type of food can be frightening, and in some instances, life threatening. Symptoms and signs of the food allergy generally develop within the hour or even just a few minutes after consuming the offending food.

The most general symptoms and signs of a food allergy include:

- Itching, eczema or hives

- Tingling or irritation in mouth

- Swelling of face, tongue, throat, lips or any other part of the body

- Nasal congestion, wheezing or even trouble breathing

- Diarrhea, abdominal pain, vomiting or nausea

- Lightheadedness, fainting or dizziness

- Abdominal cramps

The symptoms of a food allergic reaction depend on the kind of food that you have consumed. A serious food allergic reaction is known as anaphylaxis, and include extreme symptoms and signs, some of which are life threatening. They are:

- Shock, with a serious drop in blood pressure

- Rapid pulse

- Lightheadedness, dizziness or a loss of awareness or consciousness

- Constriction of the airways, which includes an inflated throat or even a lump in the throat, which makes it difficult to breathe.

Causes of food allergy

In a true food allergy, the immune system erroneously identifies a certain food component as an injurious substance. The immune system of the body triggers certain cells of the body to make E (IgE) immunoglobulin antibodies in order to fight food components or the culprit food (the allergen). The next time that you intake even the tiniest quantity of that food, the immunoglobulin (IgE) antibodies easily sense it and alerts your immune system to discharge histamine and various other chemicals into your blood stream. The released chemicals in the immune system can cause a multitude of allergic symptoms and signs. Nevertheless, histamine is to a certain extent responsible for the majority of the food allergic responses including itchy eyes, dripping nose, rashes, dry throat, nausea, labored breathing, hives and anaphylactic shocks.

The large numbers of food allergies are mainly triggered via specific proteins in:

- Peanuts

- Eggs

- Shellfish like crab, lobster and shrimp

- Fish

- Nuts like pecans and walnuts

On the other hand, in children certain proteins in the food generally trigger the allergy:

- Wheat

- Cow's milk

- Soybeans

General non-allergic associated problems include:

- Absence of the enzymes required to digest the food properly: you might not have the sufficient quantities of the particular enzymes that are required to digest certain foods. Inadequate amounts of the enzyme lactase, for example, makes it difficult to digest lactose, the prime sugar in milk products. The lactose food reaction can cause cramping, bloating, excess gas and diarrhea.

- Petulant bowel syndrome: Some foods can trigger symptoms and signs of the petulant bowel system. You might observe that some foods can cause constipation, cramping or diarrhea. Avoid the foods to keep the symptoms away.

- Food poisoning: Sometimes, the food poisoning can mimic the allergic reaction. Some kinds of rhubarb and mushrooms, for example, can be toxic. Bacteria present in tuna and various other kinds of fish can also produce a toxin, which triggers severe reactions.

- Psychological factors or recurring stress: Sometimes the simple thought of a certain food can make you allergic or sick.