What are Allergies and how do they affect you? - WALB.com, Albany News, Weather, Sports

What are Allergies and how do they affect you?

Sneezing is not always the symptom of a cold. Sometimes, it is an allergic reaction to something in the air. Experts estimate that 35 million Americans suffer from upper respiratory symptoms that are allergic reactions to airborne pollen. Pollen allergy, commonly called hay fever, is one of the most common chronic diseases in the United States. Worldwide, airborne dust causes the most problems for people with allergies. The respiratory symptoms of asthma, which affects approximately 15 million Americans, are often provoked by airborne allergens (substances that cause an allergic reaction).


What is an allergy?

An allergy is a specific immunologic reaction to a normally harmless substance, one that does not bother most people. People who have allergies often are sensitive to more than one substance. Types of allergens that cause allergic reactions include pollens, dust particles, mold spores, food, latex rubber, insect venom, or medicines.



What is an allergic reaction?

Normally, the immune system functions as the body's defense against invading agents such as bacteria and viruses. In most allergic reactions, however, the immune system is responding to a false alarm. When an allergic person first comes into contact with an allergen, the immune system treats the allergen as an invader and mobilizes to attack. The immune system does this by generating large amounts of a type of antibody (a disease-fighting protein) called immunoglobin E, or IgE. Each IgE antibody is specific for one particular allergenic (allergy-producing) substance. In the case of pollen allergy, the antibody is specific for each type of pollen: one type of antibody may be produced to react against oak pollen and another against ragweed pollen, for example.

These IgE molecules are special because IgE is the only class of antibody that attaches tightly to the body's mast cells, which are tissue cells, and to basophils, which are blood cells. When the allergen next encounters its specific IgE, it attaches to the antibody like a key fitting into a lock, signaling the cell to which the IgE is attached to release (and in some cases to produce) powerful inflammatory chemicals like histamine, cytokines, and leukotrienes. These chemicals act on tissues in various parts of the body, such as the respiratory system, and cause the symptoms of allergy.

Signs and Symptoms

The signs and symptoms are familiar to many:

  • Sneezing often accompanied by a runny or clogged nose
  • Coughing and postnasal drip
  • Itching eyes, nose, and throat
  • Watering eyes



