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Types of Allergies

An allergy is defined as an abnormal reaction by the immune system to a substance that is usually not harmful. Allergies come in a variety of forms and vary greatly in severity from mildly bothersome to life threatening. No one knows why some people develop allergies, but heredity plays a role in their development. Allergies have the potential to flare up and subside throughout a lifetime, but people rarely acquire new ones past the age of forty. Most allergic reactions are not serious, but some may result in an inability to breathe or a severe drop in blood pressure and may potentially be fatal. Only a few allergies can be completely cured, but a variety of conventional and alternative treatments are available to relieve symptoms.

Allergies come in many distinct forms and are typically grouped in general categories according to the types of substances that cause them or the parts of the body which they affect. Skin allergies are caused by direct exposure to a specific allergen and usually have no known cause. Skin allergies may result in hives due to the body's adverse reaction to certain foods, pollen, animal dander, drugs, insect stings, cold, heat, or even emotional stress. Respiratory allergies typically have symptoms which include itchy eyes, nose, and throat, along with nasal congestion, coughing, or sneezing. The terms allergic rhinitis and hay fever apply specifically to reactions caused by the pollens of ragweed, grasses, and other plants whose pollen is spread by the wind.

Food allergies are yet another type of allergy which plagues many people. An estimated 70 percent of people with food allergies are under the age of 30 and most are children under the age of 6. It can be very difficult to pinpoint the specific allergens responsible for a food allergy, but over 90% of food allergies are caused by proteins in cow's milk, peanuts, wheat, egg whites, or soybeans. Other common food allergens include berries, corn, beans, and shellfish. The classic symptoms of food allergies include diarrhea, nausea, and stomach cramps. In more severe cases there may be vomiting, swelling of the face and tongue, and respiratory congestion. Other symptoms include dizziness, sweating, and faintness.

Yet another type of allergy is those due to drugs. The most common drug allergy is to drugs in the penicillin family. Other common drug allergens include sulfas, barbiturates, anticonvulsants, insulin, and local anesthetics. Insect still allergies have been shown to affect people with food allergies more than those without. Venom in stings of bees, hornets, yellow jackets, and wasps is a common allergen. The most certain treatment for allergies is to simply avoid the substances which trigger them, but this is not always easy. The basic medications for allergies are antihistamines, which counteract the histamine chemicals which cause the allergic reactions. Prescription corticosteroid drugs may also be used for severe symptoms. Respiratory allergies are typically treated with over the counter antihistamines, but different doctors may prescribe other drugs. If symptoms are severe enough, the physician may prescribe corticosteroids in nasal spray or oral form.