Allergy is a genetic condition causing the body to respond to harmless substances in the environment as though they were dangerous invaders. This response produces symptoms that may be mild to life-threatening in susceptible people. It occurs after a person with allergic tendencies is repeatedly exposed to the substance in his/her environment or his/her diet.
When the allergic person comes into contact with the offending substance, the body's immune system rushes to the rescue and begins to produce antibodies to fight off the invader. These antibodies alter the way in which the body reacts, and may produce allergic symptoms.
Below is a list of common allergic symptoms based on each specific body part:
Is There A Name For These Offending Substances?
They are called allergens.
What Kinds of Things Are Allergens?
Anything to which a person becomes allergic is an allergen. Certain substances, because of their physical and chemical structure are more likely to become allergens than others. Prime examples are ragweed and other pollens, and penicillin. Others are dust, mold spores, animal dander, feathers, cereal grains, some air-borne chemical pollutants, drugs and insect venoms.
What Are The Most Common Allergic Symptoms?
The most common allergic symptoms are hay fever, asthma and eczema.
What Is Hay Fever?
"Hay fever" was named because of nasal symptoms developing during hay season, but most nasal allergies are called "hay fever". In "hay fever", the lining of the nose becomes irritated, causing the sufferer to sneeze and the nose to become stuffed-up or to run. Eyes may itch or turn watery. Sometimes the ears feel blocked up. "Hay fever" occurs most frequently during the spring, summer or fall when trees, grasses and weeds produce pollen. One of the principal offenders is the ragweed plant which produces pollen from late summer until frost.
What Is Asthma?
Asthma is a condition which affects breathing and the lungs. The patient wheezes, coughs, and is short of breath.
What Is Eczema?
Eczema is an inflammation of the skin. It can take the form of red patches, crusts and scales. The affected area generally itches. The condition generally occurs from eating certain foods.
Do all Allergic Responses Fall Into One Of These Categories?
No, In addition to hay fever, asthma and eczema, there can be a wide range of allergic reactions suffered in all parts of the body. For example, headaches, hives, diarrhea and stomach distress can be the result of allergy.
Is An Allergy Really A Serious Illness?
An allergic reaction can be slight and annoying or very serious. The inflamed lining of the nose of someone who suffers from hay fever can become infected, making the symptoms worse. Most dangerous of all is a sudden, heavy dose of an allergen, especially one like a bee sting or drug injection. This can trigger a generalized allergic reaction bringing on collapse or even death.
Are Allergies Inherited?
While specific allergies themselves are not inherited, the tendency towards allergies is. The more allergic one's family is, the more likely one is to develop allergies. Though the trend to develop allergies may not appear in all members of a family or even in every generation of a family, the tendency is still there.
Are Allergies Common?
It is estimated that at least 20% of the population is likely to develop some kind of allergy.
At What Age Is A Person Most Likely To Develop An Allergy?
It is most common for allergies to begin in childhood, but it is quite possible for allergic symptoms to make their first appearance at any age. You're never too old to develop an allergy.
Can An Allergy Be Outgrown?
It is common for people to change the way their other allergic symptoms affect them, especially in childhood. For example, a baby may develop colic or eczema or have recurrent ear infection, but as it grows older, it may develop other allergic symptoms such as hay fever, ear fluid or asthma. Adults may have many varied symptoms such as chronic post nasal drainage, rashes, and stomach and intestinal problems. Older patients still have a tendency to have allergic symptoms, although they may become less noticeable with maturity.
What Causes A Person To Develop An Allergy?
There is no standard way for an allergy to begin, and the onset may be sudden or gradual. For a person to become allergic to a substance, he/she must be exposed to it more than once, and generally that exposure is quite frequent. Often, symptoms develop after an unusual stress to the immune system, such as following a severe viral infection.
If I Have An Allergy, Should I Be Treated By An Allergist?
Because allergies can produce such a wide range of symptoms, there are a number of doctors, both specialists and general practitioners, in addition to allergists, who may be qualified to treat the allergic patient. For example, a skin allergy cab be effectively treated by a dermatologist (a doctor who specializes in treating skin diseases) and an infantile cow's milk allergy may be treated by the child's own pediatrician. An internist who is concerned with lung disease may also be involved with allergies that affect the lungs. An allergist may be any physician trained in the diagnosis and treatment of allergies. There are general allergists who treat allergies throughout the body and specialty allergists such as otolaryngologists (ear, nose and throat specialists), who specialize in a specific part of the body.
Should An Otolaryngologist Treat My Allergies?
An otolaryngologist is a doctor specializing in the treatment of ear, nose and throat diseases. Half of the problems he/she encounters are probably due, either directly or indirectly, to allergy. Chronic nasal congestion and post nasal drip, seasonal or constant, is often allergic and may be complicated by chronic sinus and middle ear disease. Hearing loss, dizziness, headaches, weeping ear canals, and chronic sore throats may be due to allergy. The otolaryngologist who does his/her own allergy treatment is able to follow the patient's progress with specialized examinations and nose and throat medical and surgical treatment, such as polyp removal, placement of middle ear ventilating tubes, straightening of the nasal septum, and treatment of sinus infections. An otolaryngologist not providing allergy care may refer you to a colleague for such care.
What Is The First Treatment For Allergies?
First of all, a careful history of the allergic person is taken. The most basic treatment, once an allergen has been identified, is to eliminate it. This may mean giving away a pet, avoiding certain jewelry and cosmetics, deleting certain foods from the diet, and alerting physicians about drug allergies.
What If The Allergen Can't Be Eliminated?
In the case of an allergen in the environment, such as dust, pollen, and mold a thorough house cleaning, along with other careful preventive measures, will cut down on the exposure. However, if the allergen is seasonal pollen, moving may not be the solution since there might be tree or weed pollens in the new location which could bring about the development of another, equally distressful allergic reaction. Nasal rinses can be very helpful in limiting the allergy symptoms by cleansing the nasal passageways of the allergens.
Then Are Drugs The Answer?
Drug treatment has long been a cornerstone of allergy treatment. Antihistamines and/or decongestants (for the nose) and bronchodilators (for asthma) counteract the symptoms caused by the main chemical released by the body's immune system in an allergy attack. There are other drugs, both pills and nasal sprays, which can prevent the release of these inflammatory chemicals or suppress the immune reactions themselves.
What About Cortisone?
Steroids of the cortisone family can suppress allergic reactions, but often there is the risk that the patient may develop significant side effects. Newer steroid nose sprays will often relieve allergies and not cause the side effects.
What About Allergy Shots?
Injections (immunotherapy) have been a satisfactory treatment for many inhaled allergens (that is, pollens, dust, molds and animal dander) and for bee stings. Before immunotherapy is begun, allergy tests are done in order to determine the offending allergens.
What Do The Allergy Shots Involve?
The patient is given small doses of his allergens by injection on a regular basis, usually weekly.
Is There A Standard Dosage For Everyone?
No. The appropriate allergens and their doses must be determined individually for each patient. Skin testing (placing a minute amount of the allergen under the skin) and the RAST (blood test for specific allergies) are both widely used for this purpose. Both detect the substances to which a person is allergic, as well as the degree of sensitivity, which helps determine the initial treatment dose.
How Long Will I Have To Take Shots?
The injections can bring significant relief within a few months, but may require longer. They are usually continued for 2 to 3 years. In some cases, unfortunately, it may be necessary to continue the treatment indefinitely.
How Successful Is This Treatment?
Over 80% of the patients who receive regular shots experience significant improvement or complete relief of their symptoms.
The term "In Vitro" refers to test procedures performed "outside the body," as in a laboratory, as opposed to "In Vivo" procedures performed in or on the body directly, as when allergy skin tests are performed. The allergic reaction is complex. It parallels the way the body defends itself against virus and other dangerous "foreign" invaders. Just as an antibody recognizes a virus and attaches itself to it so it may be eliminated, a substance in human blood called immunoglobulin E (IgE) also recognizes and attaches itself to allergens - the substances such as dust and pollens, which cause inhalant allergies. (Inhalants are substances which you take into your body by breathing. These include dust, pollens, molds, animal dander and tiny microscopic organisms called mites.)
Just as there are specific antibodies produced for each specific virus, specific IgE is produced for each allergen. That is, there is one type of IgE specifically for ragweed pollen, another for rye grass pollen, etc. If you have enough of a specific form of IgE in your body to cause a reaction when you breathe in one of these substances, you have an allergy.
During the first stage of allergic reaction, IgE attaches to a special cell in the tissue called the mast cell. This combination forms an allergy "bomb" that is triggered only if it contacts the IgE specific allergen. When this "bomb" explodes, it releases many chemicals, including histamine, which causes the watery eyes, runny nose, congested nose, itchy throat, and the other typical symptoms of inhalant allergies. The more the specific IgE you have, the more allergic to the allergen you are, and the stronger your body's reaction is when you breathe it.
The key to finding out what inhalants you are allergic to is to discover what specific types of IgE are present in your blood, and how much of each type is present. That sounds simple, except that we are dealing with microscopic particles which cannot be seen by the eye or identified even with the most powerful microscopes. We have to locate and measure them by very sensitive chemical tests. And that is where these In Vitro tests come in.
In Vitro tests sound very complicated, but actually they are mechanically fairly simple. Here's how they work.
As was mentioned, every allergic patient makes specific IgE to each allergen that they are allergic to. So if a drop of their blood serum or plasma (the liquid part of the blood that has been separated from the heavy blood cells) is combined with a drop of allergen, and specific IgE antibodies in the serum will attach to the allergen. In the In Vitro tests, the allergen to be tested is bound to plastic or paper, to which the serum is added.
The IgE is measured by adding a weak radioactive marker in the test tube (the Radio-allergo-sorbent test or RAST) or a chemical marker that will produce a color change (the enzyme linked immuno sorbent assay or ELISA test). These markers themselves may then be measured.
Using a tiny amount of blood serum, this test can be repeated to measure numerous allergens. This test is only recommended for inhalant allergens, as other problem substances such as foods do not usually involve IgE, and have to be tested in other ways. However, there may be some special circumstances for which your doctor orders these tests for food allergens as well.
Although the results of In Vitro tests are not available immediately, as are skin tests, they offer the convenience of requiring only one sample of blood to obtain the results for several different allergens. This is especially advantageous for children, as their discomfort is minimized.
RAST tests are very precise. As they indicate how allergic you are to each substance, they help guide your doctor to select a safe initial injection dose. If you are highly allergic to an allergen, your starting doses will be weaker than for those allergens to which you are less sensitive. This allows your treatment vials to be "tailor made" only for you. Older methods of testing could not measure the degree of sensitivity to each allergen before treatment is started. Because of this, it would often require more injections and a longer period of time to reach a therapeutic dose than with In Vitro testing. In Vitro testing can also be as cost effective as the older methods of skin testing.
In Vitro testing is extremely simple for the patient. After a thorough physical examination, your doctor will ask you to fill out a "patient history" form concerning the type of timing of your symptoms, to determine the most likely allergens you may be sensitive to, so these may be tested. Your hose and work environment (pets, trees, plants, etc.) may provide important clues as to which allergens should be tested, it is unnecessary to test for allergens to which you are not frequently exposed.
Next, a sample of blood will be drawn from your arm. The blood sample is sent to a trained laboratory technician for testing. The laboratory sends your doctor a report indicating what allergens you are sensitive to, and how allergic you are to them. After explaining the results to you, your doctor will recommend a program to deal with your allergies. This may include changing your environment (such as eliminating offending substances around your home), medications, or taking allergy injections. With proper management, most symptoms of allergy can be very well controlled.