Allergies
Allergy Causes
What Causes Allergies?
Hundreds or possibly even thousands of ordinary substances (allergens) may trigger an allergic reaction. Common allergens include:
- Animal dander
- Drugs/medications such as penicillin
- Household dust or dust mites
- Insect stings such as bee stings or fire ant stings
- Molds
- Plant pollens such as poison ivy
- Latex
- Industrial chemicals
- Cockroach droppings
- Fragrances
- Jewelry
- Cosmetics
- Other substances
One thing that makes the human body so amazing is its ability to defend itself against harmful substances and dangerous invaders, such as bacteria or viruses. However, in certain people, their body’s immune system is over sensitive and reacts defensively when exposed to allergens (generally harmless substances such as animal dander, dust, peanuts, mold, pollen or shellfish) by producing immunoglobulin E (IgE) antibodies. These antibodies attach to the receptors of a blood cell called a mastocyte (mast cell). When patients with an allergic disease (for example, asthma or allergic rhinitis) are exposed to an allergen[s], their immune system then rallies its defenses, launching a multitude of complex chemical weapons for an attack to destroy the supposedly identified “enemy.” What is happening in your body is that the allergens are binding to the IgE, which is attached to the mast cell (the main purpose of a mast cell is to destroy microorganisms invading your body). This triggers a reaction that allows the mast cells to release a variety of chemicals including histamine and leukotriene, which causes most of the symptoms of an allergy. Histamine attaches to receptors in blood vessels and causes them to enlarge. Histamine also binds to other receptors causing redness, swelling, itching and changes in secretions. During this process, unpleasant and in extreme cases life-threatening symptoms may be experienced.
Allergy Risk Factors
There is evidence that a combination of genetics and environmental factors may play a role in your allergies. While the exact genetic (inherited) factors are not yet understood, the tendency to allergies, as well as to allergic disease, is linked to heredity. Additionally, people with certain medical conditions have been linked to allergies. People with medical conditions such as asthma or other lung conditions that affect breathing, frequent infections of the nasal sinuses, ears, or respiratory tract, eczema or sensitive skin, are more likely to develop and/or have allergies. Further, your surrounding environment may aggravate your allergies: the more intense and repetitive your exposure is to allergens and the earlier in life it occurs, the more likely it is that an allergy will develop.
