Allergies Health Article

Signs and tests

The health care provider will perform a physical exam and ask questions such as when the allergy occurs.

Allergy testing may be needed to determine if the symptoms are an actual allergy or caused by other problems. For example, eating contaminated food (food poisoning) may cause symptoms similar to food allergies. Some medications (such as aspirin and ampicillin) can produce non-allergic reactions, including rashes.

Skin testing is the most common method of allergy testing. One type of skin testing is the scratch test. It involves placing a small amount of the suspected allergy-causing substances on the skin, and then slightly scratching the area so the substance moves under the skin. The skin is closely watched for signs of a reaction, which include swelling and redness. Skin testing may be an option for some young children and infants.

A blood test called RAST (radioallergosorbent) measures the levels of specific allergy-related substances. The blood test may be used if you cannot have or do not want a skin test.

Other blood tests that may help reveal allergies include:

• Antibody/immunoglobulin (particularly IgE) levels
• CBC
• Complement levels

In some cases, the doctor may tell you to avoid certain items to see if you get better, or to use suspected items to see if you feel worse. This is called "use or elimination testing." This is often used to check for food or medication allergies.

The doctor may also check your reaction to physical triggers by apply heat, cold, or other stimulation to your body and watching for an allergic response.

Sometimes, a suspected allergen is dissolved and dropped into the lower eyelid to check for an allergic reaction. This should only be done by a health care provider.

Treatment

The best way to reduce symptoms is to try and avoid what causes your allergies in the first place. This is especially important for food and drug allergies.

The most appropriate medication depends on the type and severity of symptoms. Specific illnesses that are caused by allergies (such as asthma, hay fever, and eczema) may require other treatments. Medications that can be used to treat allergies include:

ANTIHISTAMINES

• Short-acting antihistamines are generally available over-the-counter. They help relieve mild to moderate symptoms but may cause drowsiness. In addition, the short-acting antihistamine diphenhydramine (Benadryl) can affect a child's learning abilities. Loratadine (Claritin) does not tend to cause drowsiness or affect learning in children.
• Longer-acting antihistamines require a prescription. They usually do not interfere with learning. Examples of longer-acting antihistamines include fexofenadine (Allegra) and cetirizine (Zyrtec). Overall, they cause less drowsiness than other medicines, but cetirizine may cause drowsiness in some people.

NASAL SPRAYS

• Nasal corticosteroid sprays are safe and work very well for persons whose symptoms do not go away with antihistamines alone. These prescription medications include fluticasone (Flonase), mometasone (Nasonex), and triamcinolone (Nasacort AQ).
• A newer nasal spray called azelastine (Astelin) is approved for those with seasonal or environmental allergies. It is an antihistamine and not a corticosteroid.
• Cromolyn sodium is a nasal spray (NasalCrom) used to treat hay fever symptoms. (Eye drop versions are available for itchy, bloodshot eyes.)
• Decongestants can help relieve a stuffy nose. However, nasal spray decongestants should not be used for more than several days, because they can cause a "rebound" effect and make the congestion worse. Decongestants in pill form do not cause this problem.

OTHER MEDICINES

• Leukotriene inhibitors are medicines that specifically block the substances that trigger allergies. Montelukast (Singulair) is a prescription medicine approved for those with asthma and indoor and outdoor allergies.
• Allergy shots (immunotherapy) are occasionally recommended if the allergen cannot be avoided and symptoms are hard to control. Allergy shots keep your body from over-reacting to the allergen. Regular injections of the allergen are given, with each dose slightly larger than the previous dose until a maximum dose is reached. They do not work for everybody and require frequent doctor's visits.

Severe allergic reactions (anaphylaxis) require a medicine called epinephrine, which can be life saving when immediately given.