Arnese Lucks, age 11, of Vancouver, B.C., Canada, for her question:
HOW DOES AN ALLERGY DEVELOP?
Since man's earliest days he has most likely been bothered by allergies. It wasn't until the early 1900s, however, that doctors were able to understand thespecific causes and characteristics of allergies. Today there is actually a specialized field of medicine that handles only this problem area. A doctor in this branch of medicine is called an allergist.
An allergy is simply a body reaction that takesplace in a person who is sensitive to certain substances.
You can develop an allergy at any time. Most discover that first symptoms show up during childhood. About 15 percent of the population in North America today suffers from allergies that require medical assistance.
Asthma, hay fever and a year-around nasal allergy called perennial allergic rhinitis are the most common types of allergy. Allergic headaches, digestive disturbances and eczema are other types.
An allergy is caused by a substanced called an allergen. The allergens that cause most respiratory allergies can be household dust, family pets, mold spores, pollen or even dandruff. Chocolate, cow's milk, eggs, wheat and some seafoods can also trigger some allergies.
An allergy will develop when the body of an allergic person reacts to some certain allergen or allergens. Some allergens are capable of stimulating the body to produce a protein called an antibody. The allergens and the antibodies can then act together to release certain substances from the body cells into the bloodstream and other body fluids. Called H-substances, they can bring about reactions in other cells or tissues. The chief H-substance is called histamine and it can cause allergic reactions in both men and animals.
When an H-substance is released into the body it usually affects certain allergic target tissues. Most of these tissues are capillaries, mucous glands, muscles of the stomach and muscles of other organs except the heart. The location of the body tissue determines the specific allergic disease.
In general, histamine causes capillaries to enlarge, mucous glands to secrete and smooth muscles to tighten.
Such allergies as hay fever, asthma, eczema and some types of allergic headaches tend to run in families but do not seem to follow strict genetic laws. It can be said, therefore, that allergies tend to be familial rather than directly inherited.
While there seems to be no complete cures for allergies, they can definitely be controlled. Such drugs as antihistamines or cortisone are prescribed by many doctors with good results.