Allergy Testing and Treatment

Allergy Testing and Treatment

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Approximately 50 million American suffer from allergic diseases, the most common of which is allergic rhinitis. Symptoms associated with allergic rhinitis include itching of the nose and eyes, sneezing, nasal congestion, sinus pain and pressure, increased nasal secretions, and post nasal drip. Associated symptoms frequently include fluid behind the eardrum, cough, frequent throat clearing. Other commonly encountered allergic diseases include asthma and atopic dermatitis, or eczema.
 
Allergy is defined as an exaggerated physical response to substances called antigens. Typically, these responses are due to binding of antibodies to the antigen, causing a cascade of effects. Cells called mast cells present within the nose and lungs contain these antibodies, called IgE, each of which recognizes a specific antigen. If the allergic patient is exposed to the specific antigen, the mast cell releases histamine and other substances which are responsible for the development of allergic symptoms.
 
Evaluation of allergy involves detection of the IgE-mediated repsonse, either directly or by measuring levels of IgE in the bloodstream. Skin testing has been used for a century to detect abnormally sensitive responses of patients to very small amounts of antigens. Antigen is applied intradermally--within the deep layers of the skin--and the skin is observed for signs of histamine release. These include the “wheal” or swelling of the skin and “flare” or increase in redness of the skin. By observing these responses to various dilutions of antigen, clinicians can quantitatively measure the degree of allergic response observed. The other primary means of testing involves measurement of the specific antibody levels in the bloodstream. The degree of sensitivity can be determined based on the amount of specific antibody present in the bloodstream. Each of these testing methods is considered standard allergy testing and each have advantages and disadvantages. The type of testing performed is often an individual decision.
 
The simplest treatment strategy for the allergic patient is avoidance of the particular allergen. For some allergies such as peanut or egg, this is the only accepted means of treatment. Strict avoidance of these allergens prevents the development of symptoms. Other allergens such as molds or pollens are much more difficult to completely avoid and require treatment in the form of drugs or desensitization.
 
Pharmacotherapy--or the use of drugs--comes in many forms for allergy. Antihistamines have been used for decades to control the effects caused by histamine release upon exposure to allergens. First generation anithistamines such as Benadryl or Atarax are still effective, but often have unwanted side effects such as drowsiness. Second generation antihistamines have more specific binding to histamine receptors and thus prevent many of the unwanted side effects. Examples of these drugs include Claritin, Zyrtec, Allegra, and Xyzal. These drugs are commonly used for allergy patients. For patients with allergic rhinitis, nasal steroid sprays are workhorse agents. These drugs limit the inflammation caused in the nose by allergen exposure. They are generally used daily and several of the preparations can be used in children as young as two years of age. Examples include Flonase, Nasonex, Nasacort, Omnaris, Rhinocort, Veramyst. Topical antihistamine sprays such as Astelin, Astepro and Patanase have antihistamine effects confined to the nose, generally with few if any systemic side effects. The last major group of medicines are oral steroids such as prednisone, which are the most potent drugs used but also have the greatest number of side effects. Short term effects can include insomnia and mood changes, changes in blood sugar, and increased appetite and weight gain; effects of long term use include osteoporosis, changes in fat deposition, suppression of the pituitary gland, and acne. These drugs are generally used for severe allergy symptoms and in short burst doses in order to limit these effects.
 
Desensitization, or immunotherapy, is the process of exposing allergic patients to low, increasing doses of allergen in order to build a tolerance to the allergen. This is believed to be accomplished by inducing the body to create antibodies which block the release of histamine when the allergic patient is exposed to an allergen. This is accomplished by administering small doses of the allergen on a weekly basis, either with subcutaneous skin injections or drops placed beneath the tongue. The dose is escalated to a maximal dose and then this maintenance dose is then continued to be administered. Typical duration of therapy is 3-5 years. By the completion of therapy, this treatment protocol is often highly effective in preventing allergic symptoms. 
 
Southwest Idaho, Ear, Nose and Throat has been providing allergy evaluation and treatment options to patients for many years. The otolaryngologists in the practice are trained in the medical and surgical management of ear, nose, and throat disorders and are thus uniquely qualified to care for the manifestations of allergic disease. The doctors work closely with two full-time allergy nurses in both the evaluation and treatment of patients with allergic disease. Using diagnostic tools such as allergy testing, nasal endoscopy, and sinus CT scans, the treatment plan for each patient is customized in order to maximally improve symptoms as quickly and effectively as possible.

 

Educational Resources:

American Academy of Otolaryngology