Histamines are potent chemical compounds found naturally in the body. One function is to increase blood supply to an injury or a foreign substance. Though histamines aren't harmful, negative reactions can occur. Some people have an irritating, allergic response such as redness, itching and swelling. Histamines have also been linked to schizophrenia, sexual response, sleep and immune system disorders.
What are Histamines for?
The main function of histamines is to protect the body against invaders such as bacteria and viruses. When a foreign substance or allergen is in the system, white blood cells and mast cells generate the chemical histamine to fight the infection. Histamines also promote wakefulness and alertness. Antihistamines, used to ease allergy symptoms, induce fatigue because they block the effects of histamine. However, a newer generation of the medication causes less sleepiness.
Pluses and Minuses
Histamines play an important role in fighting off foreign substances, but they're also the main cause of allergies. The cells that create histamines are found in abundance in the nose, mouth, feet, internal body surfaces and blood vessels. Hay fever and other allergies, the body's reaction to histamine as an invader, affects 50 million people in the U.S., according to the National Institute of Allergy and Infectious Diseases. A National Center for Health Statistics survey found that 55 percent of all people test positive to one or more allergens.
Why Do Histamines Cause Allergies?
Genetics play a key role in who will develop allergies. The most common allergens are mold, dust mites, pollen, animal dander, cockroaches, peanuts, milk, eggs, latex and penicillin. If one parent has allergies, the risk of a child developing them is estimated at 48 percent. That risk grows to 70 percent if both parents have allergies. Each year, the incidence of allergies rise and genetics don't explain this phenomenon. It's believed that the immune system is becoming more reactive to allergens by creating histamine because of modern hygiene and health care.
Can the Body Become Less Reactive to Histamines?
People take antihistamines to reduce allergy symptoms. As the name suggests, antihistamines bond to histamine receptors and protect the body against what it sees as harmful invaders. The best way to minimize the amount of histamine released in the body is to avoid allergens. Immunologists suggest using special bedding that naturally filters small particles, dust mites and molds. It's recommended to also wash pillowcases, sheets, and mattress covers regularly in hot water. Using a vacuum cleaner with a HEPA filter prevents small allergens from being recirculated into the air, something a regular vacuum is not designed to do. Keeping an air conditioner on "Do not circulate" ensures that fresh air is pumped into the home. And after spending a day outdoors in the spring and summer, showering washes away pollens and ragweed that become attached to hair, skin and clothing.
Other Histamine Effects
Histamines are also being studied for their link to sleep and immune disorders and schizophrenia. In addition to combating disease and infection, histamine is released as a neurotransmitter in the brain to regulate sleep and increase wakefulness. The neurons fired in the brain are most frequent during waking hours; they're triggered less regularly during relaxation and stop altogether during REM sleep. When histamine production is inhibited with an antihistamine medication, drowsiness may occur. Testing has shown people who suffer from sexual problems and schizophrenia actually produce less histamine compared to those who produce a normal amount. And people who produce less of this chemical are also at higher risk for developing infections and viruses.
Tags: allergy symptoms, body against, dust mites, foreign substance, histamine released