Allergens

By Dr. Jim Ferguson

As Becky and I travel, it’s not unusual for people to ask me if I’m from Texas. I don’t wear a ten gallon hat, but apparently I have an accent confused with a Texas drawl. Actually, my accent is East Tennessean with a nasal drawl. I often respond by noting many Texans came from Tennessee, and the Volunteer State is so named because many went to help Texas in its war of independence from Mexico. Fortunately, with Becky standing beside me, it’s obvious that my “Exes aren’t in Texas.”

It’s the same thing every spring. Our eyes water, we become more nasal and some of us cough and wheeze as a result of pollen. We live in a region with water and consequently an abundance of mold, fungi and pollen. If you’ve ever walked in a forest of the Rocky Mountains, you’ll notice that trees are more widely spaced than in our Smoky Mountains, and those that fall don’t decompose as they do in our part of the world. The reason is the relative lack of water in the West, and less fungi. Actually, the abundant pollen on your car, in your eyes and nose is evidence of water, things growing and trying to propagate their species!

Some people are more sensitive to pollen, mold and dust than others. Many of these people have an allergic basis for their sensitivity and have typical allergic symptoms. Skin testing by an allergist can even identify specific pollen proteins causing trouble and the results can be used to tailor desentization inoculations. In recent years technology has been developed to measure specific antibodies to various pollen proteins in blood samples, though skin testing remains the gold standard.

Humans make five classes of antibodies (IgA, IgG, IgM, IgD and IgE) whose purpose is to help the immune system defend the body against invasion. The IgE class is associated with hay fever, asthma and parasitic infections. When these antibodies, bound to cells of the nasal and airway passages as well as the eyes and GI tract, encounter foreign protein, an intricate cellular reaction occurs, and the inflammatory response manifests as swelling and redness in the nose and eyes, along with itching, sneezing or even the bronchial spasm of asthma.

Hay fever is effectively treated with avoidance of for example ragweed. In fact, some folks move to Arizona to avoid pollen. Unfortunately, easterners sometimes take their lawns and flowers to the arid desert and reproduce their allergy problems. It’s impossible to avoid pollen at this time of the year in Tennessee, and folks with allergies often resort to medications or even allergy shots to help them cope with the allergic inflammatory response.

Therapy can be as simple as using antihistamines which counteract the chemical histamine released in the allergic cellular cascade. Doctors may also use cromolyn to “coat cells” bound with IgE. Another chemical released in the allergy cascade is leukotriene which can be inhibited with a different therapeutic class of medication. Topical steroids in drops, sprays and bronchial inhalers are also very helpful. As a last resort, desentization shots can be used which stimulate IgG antibodies and block the allergic inflammatory response. I recommend people try all the simpler methods to control their problem before resorting to expensive allergy testing and weekly or monthly allergy shots which can last for years.

Cough is one of the most common reasons a patient contacts a physician. An acute cough is one present for less than three weeks, and is often associated with viral illnesses like colds or influenza. Coughing is a symptom rather than the problem, so a proper diagnosis is necessary for treatment of a chronic cough, defined as lasting eight weeks. Everyone would cough in a smoke filled house, but a chronic cough in a smoker is especially problematic.

The most common cause of chronic cough is the “upper airway cough syndrome” associated with a post nasal drip, caused by allergic or nonallergic vasomotor rhinitis or even sinusitis. Interestingly, women have a more sensitive cough reflex than men. As an internist who deals with hypertension, cough is not infrequently associated with ACE (angiotensin converting enzyme) inhibiting drugs used to lower blood pressure. The remedy is to change the blood pressure medication. Things are sometimes not so simple and it is important to exclude various chronic lung disorders before attributing chronic cough to aggravating upper airway drainage.

The second most common cause of chronic cough is asthma which can be on an allergic basis or due to nonspecific irritants. When inflammation occurs in the lower airways, excessive mucous is produced along with swelling and spasm of the airways resulting in restricted air flow and wheezing. People with asthma complain that they can’t get a deep breath. Actually, this occurs because spasm traps air in the lungs from the previous breaths, and breathlessness occurs as with an over inflated balloon. The treatment often requires bronchodilator medications via a MDI (metered dose inhaler) to remedy air trapping.

The third major cause of chronic cough is GERD or gastroesophageal reflux disease. The esophagus is designed to carry swallowed food to the stomach where the digestive process begins with the addition of acid and pepsin, an enzyme which breaks down protein. There is a muscular area at the junction of the lower esophagus and upper stomach designed to prevent regurgitation of stomach contents back into the esophagus. When this “barrier” doesn’t function well, reflux occurs which can damage the esophageal lining and can even lead to aspiration of acid, etc. into the lungs and cause cough or pneumonia.

So, what are the take home points from this short essay? If your nasal congestion and cough are short term and associated with common cold symptoms such as malaise and low grade temperature, you don’t need an exhausting and expensive evaluation, just some comfort medication and sympathy. If pollen makes your eyes itch and water, makes you sneeze over and over or causes you to cough and wheeze, you probably have an an allergic component to your misery. And if your cough is chronic and not seasonal or causes wheezing, you should see a doctor for a proper diagnosis as a guide to treatment.

 

Sherlock Holmes might say, “Elementary my dear Watson.”

 

 

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