Allergies
More than one-third of Americans have allergies, and thousands of people do not have their symptoms under control. You may be one of them. There are three basic ways to treat allergies: avoiding the allergens that trigger your symptoms, medications, and allergy shots (also called immunotherapy or immunization). Allergies are hypersensitive reactions of the immune system to specific substances called allergens (such as pollen, stings, drugs, or food) that, in most people, result in no symptoms.

Common Allergies:

• House Dust Mites Allergy
• Food Allergy
• Pet Allergy
• Pollen Allergy
• Insect Sting Allergy
  

Dust Mites Allergy
Dust mites are microscopic organisms found in homes and are the primary cause of allergies related to dust. It is actually the excretion of these mites to which people are allergic. Therefore, dust mites can cause allergic reactions even when dead.

Food Allergy
A food allergy is any adverse reaction to a food or food component involving the body's immune system. Some adverse reactions to foods do not involve the immune system and are known as food intolerance, e.g. food poisoning or the inability to properly digest certain food components such as lactose or gliadin.

Animal Allergy
Many people are allergic to animals. Most people are not allergic to the animal's fur or feathers. The allergy is usually an immune reaction to a protein (an allergen) found in the saliva, dander (dead skin flakes), or the urine of an animal. The allergen gets carried in the air or in dust on very small, invisible particles. It then lands on the lining of the eyes (conjunctiva) and nose. It may also be inhaled directly into the lungs, causing allergic symptoms. Allergen contact with an allergic person's skin may also cause itching and hives.

Pollen Allergy
Some people have a hypersensitive reaction to pollen. While grass pollens are generally the most common cause of hay fever (seasonal allergic rhinitis), other pollen types are also important. These include tree pollens and weed pollens such as plantain, mugwort, and ragweed. The relative importance of the kinds of pollen that can cause hay fever varies between different climatic and vegetation zones. For example, ragweed pollen, although very common in North America, is present in Europe only in the French Rhône valley and some areas of Eastern Europe, while the pollen most associated with seasonal allergy in Mediterranean regions is the olive tree. A person allergic to one pollen is generally also allergic to members of the same group or family (e.g., Betulaceae). Pollen induced reactions include extrinsic asthma, rhinitis, and bronchitis.

Insect Sting Allergy
Allergic reactions to insect stings can be so severe that death may occur within the few minutes following a sting. Even if not fatal, sting allergy symptoms can be frightening and may cause dizziness; itchy welts or massive swelling of the body; inability to breathe, swallow or speak; fainting from low blood pressure; and shock.

Asthma

Asthma is a chronic lung condition that affects people of all ages; it can be severe and is sometimes fatal. It is primarily caused by inflammation of the airways which causes them to be hyper-irritated and respond with mucus production and decreased air flow. This irritability may be associated with cough, wheezing, shortness of breath, and mucus production; this condition is usually reversible with proper medical management.

The tendency to have extra-irritable (twitchy) airways may have an inherited component, or may be acquired. This tendency is, then, acted on by any of a number of stimuli (singly or in combination) including: air temperature, respiratory viruses, pollution, odors, allergens, stress, chemicals, dust, and cigarette smoke (active or passive). The two most important triggers for most people are viruses and cigarette smoke.

Spasm of bronchial smooth muscle may play a role in immediate symptoms of asthma, but this is much less a factor than previously believed. Airway inflammation is, by far, the more important factor. Some asthma can be triggered only by vigorous exercise, which causes airway irritability in susceptible individuals due to drying of airways because of rapid breathing in and out.

Resource links:

• American Academy of Allergy Asthma & Immunology. (http://www.aaaai.org)
• HON Allergy Glossary. (www.hon.ch/Library/Theme/Allergy/Glossary/allergy.html)