Allergies

Respiratory allergies affect approximately 20% of the population and contribute to numerous medical disorders of the ears, nose and throat. Symptoms can include:

  • Nasal drainage, usually clear
  • Stuffy nose
  • Sneezing
  • Watery, itchy eyes
  • Chronic cough
  • Headache
  • Asthma
  • Ear infections

What causes allergies?

Airborne pollens produced by trees, grasses, and weeds usually cause seasonal hayfever symptoms. Year round symptoms can be caused by pets, dust and insects such as cockroaches and dust mites. Molds are frequently an under recognized and therefore under treated source of allergies. Recent studies have demonstrated that even low level mold allergies may be a significant cause of chronic sinus disorders.

Allergies are caused by tiny particles called antigens which react with our immune systems. Antigens are found on pollens, pet danders, dust, molds and other substances. The immune system may react by producing a variety of antibodies. IgE antibodies are the most relevant to allergies. In allergy, an abnormal quantity of IgE antibodies are produced in response to common antigens. This results in an abnormally reactive immune system. When an antigen attaches to an IgE antibody, inflammatory mediators are released. These inflammatory mediators cause localized reactions such as swelling, irritation, inflammation and wheezing. If the allergic reaction is severe enough, life threatening systemic anaphylactic reactions can occur which require immediate medical attention.

Allergy treatment

Avoidance of the offending allergen is the obvious and most simple treatment option. Air filters will remove pollens from the air. Mattress covers and special pillow cases will protect against dust mites. Avoidance is often impossible or impractical. Most patients will get rid of their allergist before they part with their dog or cat which they’re allergic to.

Antihistamines can be taken as pills or as nasal spray or eye drops. Histamine is one of the most important inflammatory mediators involved in allergies. It causes swelling, inflammation and irritation. Antihistamines block the effect of histamine.

Nasal Sprays The nose is the organ most commonly affected by allergies. Nasal sprays administer either corticosteroids or cromolyn sodium into the nose. Corticosteroids are potent anti-inflammatory drugs which reduce the effects of inflammatory mediators. Cromolyn sodium prevents release of the inflammatory mediators in response to offending antigens.

Leukotriene Inhibitors are a new class of drugs which block the effect of inflammatory mediators.

Immunotherapy is used to repair the immune system so that fewer IgE antibodies are produced and the offending antigens are blocked by blocking antibodies. Once the offending antigens have been determined, serums of those antigens are administered by injection on a weekly basis. These serums result in the production of antibodies of a different type known as IgG. These antibodies block the antigens from reacting with the IgE antibodies. By gradually increasing the dose of antigen injected, the number of blocking antibodies is slowly increased without causing a dangerous anaphylactic reaction. Eventually, the blocking antibodies reduce the stimulation of the immune system to the point that fewer IgE antibodies are produced. The dose of antigen serum is increased until an optimum symptom relieving dose is reached. This maintenance dose is continued for several years and shots may be stopped after about five years. At this point, the symptom relieving effect of immunotherapy usually continues after the shots are stopped.

How do we test for allergies?

Testing for allergies involves various methods of testing for the presence of IgE antibodies specific for offending antigens. In allergic individuals, IgE antibodies will be present in the blood and blood tests may be used to determine the presence of allergies. IgE antibodies are also found in the skin. Skin testing is more sensitive in determining the presence of allergies and has the additional advantage that the degree of allergy to each antigen can be accurately determined. The degree of allergy or sensitivity is important because knowing this allows us to tailor the treatment to the individual patient so that it is both safe and effective.

The most popular methods of allergy testing includeMQT and intradermal testing. Since being introduced in the early 2000s, MQT has become increasing used as a method of testing in inhalant allergy and it has proven to be both sensitive and specific in clinical practice.  MQT generally employs more current, multipronged testing devices such as Mulit-Test II device because it products testing results that are more accurate and reproducible then the single-stick devices.

The antigens that are to be tested will be placed in a dipping well container and the eight multipronged devices will be dipped into this solution.  Both a positive (histamine) control and negative (glycerin) control are included in the testing board. The test antigens are then placed on the back with moderate pressure and a gentle rocking motion both from side to side and forward to backwards.  As the device is taken off the skin, small droplets of antigens will remain at the individual testing sites.

The positive wheals are measured and size recorded.  Then a single intradermal dilution will be placed on the upper outer arm for each of the positive wheals from the MQT testing.  The intradermal test results will then be used to determine the strength of the antigen to be used to make the immunotherapy serum.

In intradermal testing, a small amount of the antigen is injected into the skin which is observed for a reaction.

Intradermal testing is a very dilute solution of each antigen being injected into the skin. This tell us the strenght of antigen to start with in administering immunotherapy shots.

MQT & IDT result in a precise starting point for beginning immunotherapy. It avoids starting with too high a dose and running the risk of a life threatening anaphylactic reaction. It also allows us to start with the highest safe dose so that we can get a response to treatment as soon as possible. This has been proven to be both effective and safer than other methods of initiating immunotherapy. In fact, it is worthwhile noting that the United States Food and Drug Administration (FDA) uses skin endpoint titration as its definitive test of allergenic extracts.

Blood tests such as RAST are used to evaluate for the presence of allergies in situations where it is impractical to use skin tests. Blood tests do not quantitate the degree of sensitivity as accurately as skin tests do. Therefore the optimal starting dose for immunotherapy is more difficult to determine which results in a more conservative initial dose for immunotherapy, hence the optimal dose for relief of symptoms is not reached as quickly. We use RAST technology when SET is impractical.

Why choose an otolaryngic allergist?

An otolaryngic allergist is an ear nose and throat specialist who has undergone at least five years of post-doctoral training. Most symptoms caused by allergies can be caused by other disorders. The otolaryngic allergist is uniquely qualified to diagnose and treat both allergic and non-allergic disorders of this region of the body.

 


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