Causes of Allergies

An allergy is defined as an inappropriate response by the body's immune system to any substance that would normally be considered harmless to most people. During an allergic reaction, the immune system mistakenly identifies a substance that is non-toxic as a harmful aggressor. This causes the white blood cells that normally protect against the body's invaders to react against this harmless agent, thus creating a response worse than the aggressor itself. The problem is that there are many different kinds of substances that can cause this reaction.

Mold

• Mold is a major cause of allergies. Mold is a microscopic living organism that is able to live where other life forms cannot. Mold flourishes in damp, dark places and can be spread through the air as well as on organic substances with which people regularly come into contact. While mold can be beneficial to humans, such as in making cheese and penicillin, it is also one of the most dangerous substances for creating allergic reactions. People with allergies to mold can be exposed from normal daily activities that range from walking through a wooded area to cutting the grass and repairing old furniture.

Food

• Many people confuse a food allergy with a simple intolerance. Intolerance means that a person has trouble digesting or processing certain foods, most often because they lack a certain enzyme or combination of enzymes. An allergic reaction to food takes place when one's immune system produces an antibody response to food that has been consumed. Food allergies might be stimulated by an intolerance to a food, which allows undigested particles to enter the bloodstream.

Seasonal Allergies

• Season allergies are among the most common types of allergies and are caused by certain plants. Of these seasonal allergies, the most common is hay fever. That term is a misnomer, however, since most hay fever has nothing to do with hay. Instead, hay fever is caused by pollen released by flowering plants. Because most plants that produce pollen flower in the spring, that is the season where one is most likely to be affected by hay fever.

Furry Animals

• Some people unfortunately discover they are ill-prepared to be pet owners because they develop allergies to dander. In fact, it is not really the fur or hair that people are allergic to, but rather the pollen, dust and mold that gets collected in the fur. Others might experience similar allergic reactions to animals because of their droppings and, in the case of birds, their feathers.

Sulfite Allergies

• Some people who believe they have food allergies actually turn out to be allergic to sulfites. Sulfites are food additives used as preservatives to prevent discoloration. The severity of a sulfite allergy can range from difficulty breathing to anaphylactic shock. Common foods containing sulfites include coleslaw, potatoes, frozen French fries, beer, olives and oysters.

Contact Allergies

• Contact allergies occur when a person touches a particular object or substance that usually results in a rash, typically at the spot where the contact was made. An allergic reaction can be caused even by substances that normally adversely affect others. For instance, almost everybody has some kind of allergic reaction to poison ivy, but there are people who are far more susceptible and whose reactions are more extreme. In addition, these people can often experience an allergic reaction simply by touching someone else who has come into contact with the poisonous plant.