Tips to Remember: What is Allergy Testing?

You are sneezing, wheezing and coughing. Your eyes are itchy and your nose is running. When you visit your doctor, she says you may have allergies. But to find out exactly what is making you sneeze, you’ll need to have allergy testing done.

What is allergy testing?
If you are allergic, you are reacting to a particular substance. Any substance that can trigger an allergic reaction is called an allergen. To determine which specific substances are triggering your allergies, your allergist will safely and effectively test your skin, or sometimes your blood, using tiny amounts of commonly troublesome allergens. Allergy tests are designed to gather the most specific information possible so your doctor can determine what you are allergic to and provide the best treatment.

Which allergens will I be tested for?
Because your physician has made a diagnosis of allergies, you know that one or more allergens is causing your allergic reaction—itching, swelling, sneezing, wheezing, and other symptoms. Your symptoms are probably caused by one of these common allergens:

• products from dust mites (tiny bugs you can’t see) that live in your home;
• proteins from furry pets, which are found in their skin secretions (dander), saliva and urine (it’s actually not their hair);
• molds in your home or in the air outside;
• tree, grass and weed pollen; and/or
• cockroach droppings.

More serious allergic reactions can be caused by:

• venoms from the stings of bees, wasps, yellow jackets, fire ants and other stinging insects;
• foods;
• natural rubber latex, such as gloves or balloons; or
• drugs, such as penicillin.

All of these allergens are typically made up of proteins. Allergy tests find which of these proteins you may be reacting to.

The allergen extracts or vaccines used in allergy tests are made commercially and are standardized according to U.S. Food and Drug Administration (FDA) requirements. Your allergist is able to safely test you for allergies to substances listed above using these allergen extracts.

What are specific types of allergy tests?
Scratch or puncture test—These tests are done on the surface of the skin. A tiny amount of allergen is scratched across or lightly pricked into the skin. If you have an allergy, the specific allergens that you are allergic to will cause a chain reaction to begin in your body.

People with allergies have an allergic antibody called IgE (immunoglobulin E) in their body. This chemical, which is only found in people with allergies, activates special cells called mast cells. These mast cells release chemicals called mediators, such as histamine, the chemical that causes redness and swelling. With testing, this swelling occurs only in the spots where the tiny amount of allergen to which you are allergic has been scratched onto your skin. So, if you are allergic to ragweed pollen but not to cats, the spot where the ragweed allergen scratched your skin will swell and itch a bit, forming a small dime-sized hive. The spot where the cat allergen scratched your skin will remain normal. This reaction happens quickly within your body.

Test results are available within 15 minutes of testing, so you don’t have to wait long to find out what is triggering your allergies. And you won’t have any other symptoms besides the slightly swollen, small hives where the test was done; this goes away within 30 minutes.

Intradermal test—This test is related to the scratch or puncture test, but is slightly more sensitive. It involves injecting a tiny amount of allergen under the skin, usually on the upper arms. Your allergist may do this test when your reaction to the scratch test cannot be clearly determined.

Blood (RAST) test—Sometimes your allergist will do a blood test, called a RAST (radioallergosorbent) test. Since this test involves drawing blood, it costs more, and the results are not available as rapidly as skin tests. RAST tests are generally used only in cases in which skin tests can not be performed, such as on patients taking certain medications, or those with skin conditions that may interfere with skin testing.

Challenge tests—These tests are done only if specific allergy testing is not available, and the patient needs the food or medication to which they may be allergic. The test involves having the patient inhale or swallow a very small amount of the suspected allergen, such as milk or an antibiotic. If there is no reaction, the dose may be slowly increased. Since challenge tests may induce severe allergic reactions, they are only done when absolutely necessary, and must be closely supervised by an allergist.

The American Academy of Allergy, Asthma and Immunology, along with many other medical associations, considers some allergy testing methods to be unacceptable in medical practice. According to an AAAAI position statement, these unacceptable tests include cytotoxicity testing, urine autoinjection, skin titration (Rinkel method), provocative and neutralization (subcutaneous) testing or sublingual provocation. If your physician plans to conduct any of these tests on you, please see an allergist for proper allergy testing.

Who can be tested for allergies?
Adults and children of any age can be tested for allergies. Because different allergens bother different people, your allergist will take your medical history to determine which test is the best for you. Some medications can interfere with skin testing. Antihistamines, in particular, can inhibit some of the skin test reactions. Use of antihistamines should be stopped one to several days prior to skin testing.

Reasons for allergy testing
To help you manage your allergy symptoms most effectively, your allergist must first determine what is causing your allergy. For instance, you don’t have to get rid of your cat if you are allergic to dust mites but not cats, and you don’t need to take medication all year if you have a seasonal allergy to ragweed.

Allergy tests provide concrete information. And once you know the specific allergens causing your symptoms, you can try to:

1. avoid exposure to the allergens;
2. get specific medical treatment; and
3. if necessary, consider specific vaccination with the allergen, or "allergy shots."

Tips to Remember: Asthma & Allergy Medications

More than 50 million people in the U.S. suffer from asthma and allergies. Fortunately, today there are many effective medications available to treat these conditions. The following information is intended to help asthma and allergy sufferers better understand the most commonly used types of medications.

Antihistamines
If you have allergies, your physician may prescribe antihistamines, which are used to relieve or prevent the symptoms of allergic rhinitis (hay fever) and other allergies. Antihistamines can lessen your symptoms by preventing the effects of histamine—a chemical substance produced by the body during an allergic reaction. Antihistamines, which come in tablet, capsule, liquid or injection form, are available by prescription as well as over-the-counter.

Most over-the-counter antihistamines can cause drowsiness. Newer prescription antihistamines rarely cause this side effect. Other common side effects of antihistamines include dehydration—dry mouth, difficulty urinating, dry eyes or constipation. After taking antihistamines, some children may experience nightmares, unusual jumpiness or nervousness, restlessness or irritability.

Decongestants
Decongestants are used to treat nasal congestion and other symptoms associated with colds and allergies. They work by shrinking blood vessels, thereby decreasing the amount of fluid that leaks out and lessening nasal congestion. Decongestants are available in liquid and tablet form, both over-the-counter and by prescription. Many medications combine both antihistamines and decongestants to relieve a larger range of symptoms. Side effects of decongestants can include nervousness, sleeplessness or elevation in blood pressure.

Decongestants are also available in nose spray or drop form for acute congestion. However, over-the-counter nasal sprays should not be used more than three to four days in a row. If used for a prolonged period of time, over-the-counter nose sprays can cause "rebound rhinitis," actually increasing your nasal congestion. Prescription nasal sprays and drops do not have this effect and can be used for longer periods of time, as prescribed by your physician.

Anti-inflammatory agents
People with asthma have inflamed airways. This inflammation causes the bronchi—the main branches leading from the throat to the lungs—to become overly reactive. The airways are more sensitive to various asthma triggers such as allergens, cold and dry air, smoke and viruses. Anti-inflammatory agents such as cromolyn, nedocromil and corticosteroids reduce inflammation and asthma symptoms. Cromolyn and nedocromil are non-steroidal and usually are prescribed in the inhaled form, while corticosteroids are prescribed in both the inhaled (topical) and oral form.

Corticosteroids are sometimes also referred to as "steroids." This type of medication is not related to the anabolic steroids that are misused by some athletes to increase performance. Rather, corticosteroids have been used as a successful treatment for asthma and allergies since 1948. They decrease airway inflammation and swelling in the bronchial tubes; reduce mucus production by the cells lining the bronchial tubes; decrease the chain of overreaction (hyperreactivity) in the airways; and help the airway "smooth muscle" respond to other medications.

Corticosteroids can be administered in a variety of ways. Topical preparations (on specific surface areas such as skin or the lining of the bronchial tubes) may be applied as creams or sprays (inhalers). Corticosteroid inhalers are recommended for patients with daily, moderate or severe asthma symptoms. Oral corticosteroids may be ingested in a liquid or tablet form, or may be administered by injection. They are generally only prescribed for those with severe asthma symptoms.

Some people may experience minor side effects of hoarseness and thrush (a fungal infection of the mouth and throat) from using corticosteroid inhalers. Such problems can be minimized by mouth-rinsing and using a spacer device, which can reduce the amount of medication residue in the mouth and throat. Although there are conflicting studies, long-term use of inhaled corticosteroids may result in reduced growth velocity in children. However, control of asthma symptoms may be of greater importance. If you are concerned about your child using these medications on a long-term basis, see your physician for more information.

Oral corticosteroids can have more side effects than inhaled corticosteroids. Long-term use of oral corticosteroids is not recommended, except in cases of uncontrolled, severe asthma. Your doctor will prescribe oral steroids for long durations only when other treatments have failed to restore normal lung function and the risks of uncontrolled asthma are greater than the side effects of the steroids. Prednisone, one of the most commonly prescribed steroid drugs, is available in tablet or liquid form. Possible side effects of short-term prednisone use include slight weight gain, increased appetite, menstrual irregularities and cramps, heartburn, or indigestion. Some patients experience side effects such as loss of energy, poor appetite, and severe muscle aches or joint pains when their dosage of cortisone tablets is decreased. If you are taking oral steroids, your physician will taper your dosage slowly for weeks or months to avoid effects of withdrawal.

Long-term oral corticosteroid use may cause side effects such as ulcers, weight gain, cataracts, weakened bones and skin, high blood pressure, elevated blood sugar, easy bruising and decreased growth in children. If you have questions or concerns about long-term oral steroid use, make sure to discuss them with your physician.

Corticosteroids, when taken properly, are a very effective method of treatment for asthma and allergies. To achieve their desired effects, you should always take them in the dosage prescribed. Do not increase or decrease your medication without first consulting your physician. Also, it is important to follow the prescribed frequency and use the proper inhaler technique to administer the medication.

Anti-leukotrienes
Many of the cells involved in causing airway inflammation are known to produce potent chemicals within the body called leukotrienes (lu-ko-try-eens). Leukotrienes are responsible for inciting a riot within the body—causing the contraction of the airway smooth muscle, increasing leakage of fluid from blood vessels in the lung, and further promoting inflammation by attracting other inflammatory cells into the airways.

Recently, oral anti-leukotriene medications have been introduced to fight the inflammatory response typical of allergic disease. These drugs are used in the treatment of chronic asthma. Recent data demonstrates that prescribed anti-leukotriene medications can be beneficial for many patients with asthma. Additionally, many patients may find it easier and prefer taking an oral rather than an inhaled medication. These newer medications will eventually have an increased role in asthma care as more studies are conducted.

Bronchodilators
Bronchodilators are generally used as asthma "rescue medications" to relieve coughing, wheezing, shortness of breath and difficulty in breathing. They work by opening up the bronchial tubes—the air passages in the lungs—so that more air can flow through. Bronchodilators include beta-agonists, theophylline and anticholinergics. They come in inhaled, tablet, capsule, liquid or injectable forms.

Salmeterol is a long-acting bronchodilator that, along with an anti-inflammatory medication, is used for maintenance in the control of asthma symptoms. Other bronchodilators are intended to be used as rescue medications only during asthma flare-ups or when regular maintenance therapies are not working. Side effects of bronchodilators can include nervousness, restlessness and insomnia, and rarely, headache. Elderly patients and children may be more sensitive to the effects of these medications.

To treat your allergy and asthma symptoms, your allergist will prescribe the medications that are best for you and your specific symptoms. If you have side effects from any medications, be sure to contact your doctor.

Tips to Remember: Allergic Skin Conditions

Red, bumpy, scaly, itchy, swollen skin—any of these symptoms can signify an allergic skin condition. These skin problems are often caused by an immune system reaction, signifying an allergy. Allergic skin conditions can take several forms and are due to various causes.

Hives and angioedema
Hives or urticaria are red, itchy, swollen areas of the skin that can range in size and appear anywhere on the body. Approximately 25% of the U.S. population will experience an episode of hives at least once in their lives. Most common are acute cases of hives, where the cause is identifiable—often a viral infection, drug, food or latex. These hives usually go away spontaneously. Some people have chronic hives that occur almost daily for months to years. For these individuals, various circumstances or events, such as scratching, pressure or "nerves," may aggravate their hives. However, eliminating these triggers has little effect on this condition.

Angioedema, a swelling of the deeper layers of the skin, sometimes occurs with hives. Angioedema is not red or itchy, and most often occurs in soft tissue such as the eyelids, mouth or genitals. Hives and angioedema may appear together or separately on the body. Hives are the result of a chemical called histamine—responsible for many of the symptoms of allergic reactions—in the upper layers of the skin. Angioedema results from the actions of these chemicals in the deeper layers of the skin. These chemicals are usually stored in our bodies’ mast cells, which are cells heavily involved in allergic reactions. There are several identifiable triggers that release histamine and other chemicals from the mast cells, causing hives.

In adults, reactions to medicines are a common cause of acute hives. Medications known to cause hives or angioedema include aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, high blood pressure medicines known as ACE-inhibitors, or pain-killers containing codeine or codeine-like drugs. Like all drug-induced hives, these reactions occur within only minutes to an hour of taking the drug. Adults can also develop hives after eating certain foods, including nuts, eggs, shellfish, soy, wheat or milk—the culprits in more than 90% of proven food-induced hives. In children, foods or viral infections such as a cold can trigger acute hives. Physical urticaria are hives resulting from an outside source: rubbing of the skin, cold, heat, physical exertion or exercise, pressure or direct exposure to sunlight. Patients with chronic urticaria often report that at least one of these triggers induces their hives.

Whenever there is an identifiable trigger of hives, it should be eliminated. In patients with acute hives, some drugs or foods may take days to be eliminated from the body. For these individuals, an allergist may prescribe antihistamines to relieve symptoms until the culprit is eliminated. For patients with chronic hives, treatment cannot control the eruptions; these hives will eventually disappear on their own, with or without treatment. For 50% of these patients, the hives will clear in three to 12 months; 40% will clear in one to five years. Up to 1.5% of these patients may experience these hives for more than 20 years.

Forty percent of patients with chronic hives will have at least one more episode of chronic hives in their lifetime. For these patients, the treatment objective is to provide comfort. If you experience chronic hives, your allergist will prescribe antihistamines, and will combine medications and adjust your dosages as needed for your individual symptoms. In rare cases, if antihistamines do not provide appropriate comfort, the allergist will prescribe an oral corticosteroid.

Contact dermatitis
When some substances come into contact with skin, they may cause a rash called contact dermatitis. Some of these reactions are the result of an allergic reaction that involves the immune system, but many are the result of a non-allergic, or irritant, reaction. Often, it is difficult to tell the difference between these two types of reactions. The hallmark of allergic contact dermatitis is that it occurs almost exclusively where the offending agent—such as a plant or chemical—comes in contact with the skin.

Irritant contact dermatitis is often more painful than itchy, and is the result of an offending agent that actually damages the skin with which it comes into contact. The longer the skin is in contact—or the more concentrated the agent—the more severe the reaction. Water with added soaps and detergents is the most common cause. Thus, it is not surprising that these reactions appear most often on the hands, and are frequently work-related. Individuals with other skin diseases, especially eczema (ex-zeh-ma), are most susceptible.

Allergic contact dermatitis is best exemplified by the itchy, red, blistered reaction that almost everyone experiences after touching a plant in the "rhus" family—poison ivy, poison oak or poison sumac. This allergic reaction is caused by a chemical in the plant called urushiol. You can have a reaction from touching other items with which the plant has come into contact, including yard tools or the family dog. However, once your skin has been washed, you cannot get another reaction from touching the rash or blisters. Unlike irritant contact dermatitis, which occurs within minutes of coming into contact with an offending agent, allergic contact dermatitis reactions can occur 24-48 hours after contact. Once a reaction starts, it takes 14-28 days to resolve, even with treatment.

Other agents that frequently cause allergic contact dermatitis include nickel, perfumes and fragrances, dyes, rubber (latex) products and cosmetics. Some ingredients in medications applied to the skin also can cause an allergic reaction, most commonly neomycin, an ingredient in antibiotic creams. To avoid reactions, any cream that ends in "caine" should never be applied to damaged skin.

Treatment of irritant contact dermatitis requires that the skin be kept from contact with the agent that is causing the reaction, and that every precaution is taken to avoid spilling caustic chemicals on the skin. Gloves can sometimes be helpful. Since these reactions are non-allergic in nature, treatment is directed toward relieving symptoms and preventing any permanent damage to the affected skin.

Treatment for allergic contact dermatitis depends on the severity of the symptoms. Cold soaks and compresses can offer relief for the acute, early, itchy blistered stage of the rash. When the rash is limited to small areas of the skin, topical corticosteroid creams may be prescribed to offer relief. When large areas of the body are involved, oral corticosteroids may be prescribed. If prescribed, it is important to continue to take oral medications for the entire duration of the reaction (14-28 days). To prevent the reaction from recurring, make sure to avoid contact with the offending substance. If the patient and allergist cannot determine the substance that caused the reaction based on the patient’s history, the allergist may conduct a series of patch tests to help identify it.

Atopic dermatitis/eczema
A common allergic reaction often affecting the face, elbows and knees is atopic dermatitis, also known as eczema. This red, scaly, itchy rash is usually seen in young infants, but can occur later in life in individuals with personal or family histories of atopy, meaning asthma or allergic rhinitis ("hay fever"). Eczema may at times ooze, or at times may look very dry. A physician will rarely have difficulty diagnosing atopic dermatitis, based on three factors: an 1) itchy, 2) "eczematous" or bubbly rash in an 3) atopic individual. If one of these three features is missing, your physician should consider other causes.

Identifying the cause of the itch is essential in managing symptoms. Common triggers include overheating or sweating, and contact with irritants such as wool, pets or soaps. In older individuals, emotional stress can cause a flare-up. For some patients, usually children, food can also trigger eczema. Secondary staph infections also can cause a flare-up in children. These patients usually have very dry skin and "allergic shiners"—an extra crease, called a Dennie’s line, across their lower eyelids. They are also more susceptible to other skin infections.

Preventing the eczema itch is the primary goal of treatment. The patient must stop scratching and rubbing the rash. Applying cold compresses is helpful, and lubricating the dry skin with cream or ointment, especially during dry seasons, is essential. Patients should remove all "irritants" that aggravate the condition from their environments. If a food is identified as the culprit, it must be eliminated from the diet.

Topical corticosteroid cream medications are most effective in treating the rash once all preventative measures are taken. Rarely, antihistamines or oral corticosteroids are also prescribed, and if a secondary infection has been introduced by scratching, antibiotics are required.