Allergy is a disorder of the immune system often also referred to as atopy. Allergic reactions occur to environmental substances known as allergens; these reactions are acquired, predictable and rapid. Strictly, allergy is one of four forms of hypersensitivity and is called type hypersensitivity. It is characterized by excessive activation of certain white blood cells called mast cells and basophils by a type of antibody known as IgE, resulting in an extreme inflammatory response. Common allergic reactions include eczema, hives, hay fever, asthma, food allergies, and reactions to the venom of stinging insects such as wasps and bees.

Why Do People Get Allergies?

The tendency to develop allergies is often hereditary, which means it can be passed down through your genes. (Thanks a lot, Mom and Dad!) However, just because a parent or sibling might have allergies, that doesn't mean you will definitely get them, too. A person usually doesn't inherit a particular allergy, just the likelihood of having allergies.

What Causes Allergies?

A healthy immune system is balanced between the activity of 2 types of white blood cells, called Th1 and Th2.

Genetic or environmental factors can cause a Th2 dominated response to develop which can lead to allergies.

The use of immunizations and antibiotic therapies and increased pollution leads to Th2 dominance.

Once an imbalance in T cells develops, it tends to be continued by production of chemicals (cytokines) that keep the imbalance in place.

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.

Allergy Symptoms

For allergy symptoms such as a runny nose, watery/itchy eyes, or sneezing that occur infrequently, most individuals can be treated sucessfully with an oral non-sedating antihistamine such as loratadine (Claritin), desloratadine (Clarinex), fexofenadine (Allegra), cetirizine (Zyrtec), levocetirizine (Xyzal) or or an antihistamine nasal spray such as azelastine (Astelin) to be taken on an as needed basis when allergy symptoms arise.

Allergy Treatment

An effective allergy treatment is a concern for anyone suffering from seasonal allergies or asthma. Like many other medical conditions, allergies are affecting a growing portion of society. Serious diseases like cancer, heart disease and stroke seem to be rising at about the same rate along with allergies.

Topical nasal steroids. This class of allergy medications is probably the most effective at treating nasal allergies, as well as non-allergic rhinitis. There are numerous topical nasal steroids on the market, and are all available by prescription. Some people note that one smells or tastes better than another, but they all work about the same.

Allergies to Pets

Studies show that approximately 15 percent of the population is allergic to dogs or cats. An estimated one-third of Americans who are allergic to cats (about two million people) live with at least one cat in their household anyway. In a study of 341 adults who were allergic to cats or dogs and had been advised by their physicians to give up their pets, only one out of five did. What's more, 122 of them obtained another pet after a previous one had died.