Treatment of Allergies
If you cannot adequately avoid airborne allergens, your symptoms often can be controlled by medicines. You can buy medicines without a prescription that can relieve allergy symptoms. If, however, they don’t give you relief or they cause unwanted side effects such as sleepiness, your health care provider can prescribe antihistamines and topical nasal steroids. You can use either medicine alone or together.
As the name indicates, an antihistamine counters the effects of histamine, which is released by the mast cells in your body’s tissues and contributes to your allergy symptoms. For many years, antihistamines have proven useful in relieving itching in the nose and eyes; sneezing; and in reducing nasal swelling and drainage.
Many people who take antihistamines have some distressing side effects such as drowsiness and loss of alertness and coordination. Adults may interpret such reactions in children as behavior problems.
Antihistamines that cause fewer of these side effects are available over-the-counter or by prescription. These non-sedating antihistamines are as effective as other antihistamines in preventing histamine-induced symptoms, but most do so without causing sleepiness.
Topical Nasal Steroids
You should not confuse topical nasal steroids with
anabolic steroids, which athletes sometimes use to enlarge
muscle mass and which can have serious side effects.
The chemicals in nasal steroids are different from those
in anabolic steroids.
Topical nasal steroids are anti-inflammatory medicines that stop the allergic reaction. In addition to other helpful actions, they decrease the number of mast cells in the nose and reduce mucus secretion and nasal swelling. The combination of antihistamines and nasal steroids is a very effective way to treat allergic rhinitis, especially if you have moderate or severe allergic rhinitis.
Although topical nasal steroids can have side effects, they are safe when used at recommended doses.
Cromolyn sodium is a nasal spray that in some people helps prevent allergic rhinitis from starting. When used as a nasal spray, it can safely stop the release of chemicals like histamine from mast cells. It has few side effects when used as directed and significantly helps some people manage their allergies.
Sometimes helping the nasal passages to drain away mucus will help relieve symptoms such as congestion, swelling, excess secretions, and discomfort in the sinus areas that can be caused by nasal allergies. Your doctor may recommend using oral or nasal decongestants to reduce congestion along with an antihistamine to control allergic symptoms.
You should not, however, use over-the-counter or prescription decongestant nose drops and sprays for more than a few days. When used for longer periods, these medicines can lead to even more congestion and swelling of the nasal passages. Because of recent concern about the bad effects of decongestant sprays and drops, some have been removed from store shelves.
Immunotherapy, or a series of allergy shots, is the only available treatment that has a chance of reducing your allergy symptoms over a longer period of time. You would receive subcutaneous (under the skin) injections of increasing concentrations of the allergen(s) to which you are sensitive. These injections reduce the level of IgE antibodies in the blood and cause the body to make a protective antibody called IgG.
About 85% of people with allergic rhinitis will see their hay fever symptoms and need for medicines drop significantly within 12-months of starting immunotherapy. Those who benefit from allergy shots may continue it for 3-years and then consider stopping. While many are able to stop the injections with good results lasting for several years, others do get worse after the shots are stopped.
One research study shows that children treated for allergic rhinitis with immunotherapy were less likely to develop asthma. Researchers need to study this further, however. As researchers produce better allergens for immunotherapy, this technique will be become an even more effective treatment.
Research on allergies is focused on understanding what happens to the human body during the allergic process — the sequence of events leading to the allergic response and the factors responsible for allergic diseases.
Scientists supported by NIAID found that, during the first years of their lives, children raised in a house with two or more dogs or cats may be less likely to develop allergic diseases as compared with children raised without pets. The striking finding here is that high pet exposure early in life appears to protect some children from not only pet allergy but also other types of common allergies, such as allergy to house dust mites, ragweed, and grass. This new finding is changing the way scientists think about pet exposure. Scientists must now figure out how pet exposure causes a general shift of the immune system away from an allergic response.
The results of this and a number of other studies suggest that bacteria carried by pets may be responsible for holding back the immune system's allergic response. These bacteria release molecules called endotoxin. Some researchers think endotoxin is the molecule responsible for shifting the developing immune system away from responding to allergens through a class of lymphocytes called Th-2 cells. (These cells are associated with allergic reactions.) Instead, endotoxin may stimulate the immune system to block allergic reactions.
If scientists can find out exactly what it is about pets or the bacteria they carry that prevents the allergic response, they might be able to develop a new allergy treatment.
Some studies are seeking better ways to diagnose as well as treat people with allergic diseases and to better understand the factors that regulate IgE production to reduce the allergic response. Several research institutions are focusing on ways to influence the cells that participate in the allergic response.
NIAID supports a network of Asthma, Allergic and Immunologic Diseases Cooperative Research Centers throughout the United States. The centers encourage close coordination among scientists studying basic and clinical immunology, genetics, biochemistry, pharmacology, and environmental science. This interdisciplinary approach helps move research knowledge as quickly as possible from the lab into the hands of doctors and their allergy patients.
Educating patients and health care providers is an important tool in controlling allergic diseases. All of these research centers conduct and evaluate education programs focused on methods to control allergic diseases.
Since 1991, researchers participating in NIAID’s
Inner-City Asthma Study have been examining ways to
treat asthma in minority children living in inner-city
environments. Asthma, a major cause of illness and hospitalizations
among these children, is provoked by a number of possible
factors, including allergies to airborne substances.
The success of NIAID’s model asthma program led the U.S. Centers for Disease Control and PREVENTION to award grants to help community-based health organizations throughout the United States implement the program.
Based on the success of the first National Cooperative
Inner-City Asthma Study, NIAID and the National Institute
of Environmental Health Sciences, also part of NIH,
started a second cooperative multi center study in 1996.
This study recruited children with asthma, aged 4 to
11, to test the effectiveness of two interventions.
One intervention uses a novel communication and doctor
education system. Information about the children’s
asthma severity is provided to their primary care physicians,
with the intent that this information will help the
doctors give the children the best care possible.
The other intervention involves educating families about reducing exposure to passive cigarette smoke and to indoor allergens, including cockroach, house dust mite, and mold. Researchers are assessing the effectiveness of both interventions by evaluating their capacity to reduce the severity of asthma in these children.
Early data show that by reducing allergen levels in children’s beds by one-third, investigators reduced by nearly one-quarter (22%) both the number of days the children wheezed and the number of days the children missed school.
Although several factors provoke allergic responses, scientists know that heredity plays a major role in determining who will develop an allergy. Therefore, scientists are trying to identify and describe the genes that make a person susceptible to allergic diseases.
Because researchers are becoming increasingly aware
of the role of environmental factors in allergies, they
are evaluating ways to control environmental exposures
to allergens and pollutants to prevent allergic disease.
These studies offer the promise of improving the treatment and control of allergic diseases and the hope that one day allergic diseases will be preventable.
Glossary of Allergy Terms
Allergen — substance that causes an allergic reaction
Allergenic — describes a substance which produces an allergic reaction
Antibody — molecule tailor-made by the immune system to lock onto and destroy specific germs
Basophils — white blood cells that contribute to inflammatory reactions
Conjunctivitis — inflammation of the lining of the eyelid, causing red-rimmed, swollen eyes, and crusting of the eyelids
Genes — units of genetic material that carry the directions a cell uses to perform a specific function
Granules — small particles; in cells the particles typically include enzymes and other chemicals
Immune System — a complex network of specialized cells, tissues, and organs that defends the body against attacks by disease-causing organisms
Inflammation — an immune system process that stops the progression of disease-causing organisms
Lymphocytes — small white blood cells which
are important parts of the immune system
Mast Cells — granule-containing cells found in tissue
Molecules — the building blocks of a cell. Some examples are proteins, fats, and carbohydrates organism—an individual living thing perennial—describes something that occurs throughout rhinitis—inflammation of the nasal passages, which can cause a runny nose sinuses—hollow air spaces located within the bones of the skull surrounding the nose
Sputum — matter ejected from the lungs and windpipe through the mouth tissues—groups of similar cells joined to perform the same function upper respiratory tract—area of the body which includes the nasal passages, mouth, and throat