An allergy is an abnormal reaction of the body's immune system to a substance in the environment that, for most people, causes no immune response…

Almost anything can trigger an allergic reaction in sensitive people. Exposure to allergens can occur through the air, by touch, or by ingestion…

When exposure to an allergen occurs through touch or ingestion, symptoms can vary from itching, hives, flushed appearance, runny nose, and nasal congestion to more severe reactions which can cause nausea, vomiting, abdominal pain, trouble breathing, and difficulty swallowing due to swelling of the face and tongue (angioedema)…

The immune system normally protects the body from foreign invaders that cause harm such as viruses and bacteria. During an allergic reaction the immune system turns its defenses against a substance that does not normally cause disease, one that is ignored by the immune system of people without allergies, resulting in the symptoms of allergies…

Allergies have a strong hereditary component meaning you have a greater chance of developing allergies if one or both of your parents has them. However, scientists do not believe that people inherit sensitivity to specific allergens, but instead inherit a general tendency to develop some type of allergy…

The symptoms of allergies are very similar to those of the common cold so it may be difficult to distinguish between the two. A good rule of thumb is when cold-like symptoms last longer than one or two weeks, or if you tend to have frequent colds, you may want to consult your doctor to discuss being tested for allergies…

Several treatments are available to treat allergies including both over the counter and prescription drugs: antihistamines, nasal sprays, immunotherapy, and emergency shots…

Even if you have never experienced an allergic reaction before, there is no way to ensure that you will not in the future. In fact, a person can develop allergies at any age…