Allergies affect 20 percent of Americans. There is a genetic tendency toward the development of allergic disease and patients can develop allergies at any age. The symptoms of allergic rhinitis may mimic those of sinusitis or a viral respiratory tract infection (the common cold). The table below serves as a guideline to differentiate between the signs and symptoms of these common conditions.
Allergies occur when environmental triggers, such as pollens, mold spores, or animal dander, come into contact with the lining of the nose, eyes or throat. In certain patients, the immune system is hyperactive and produces an exuberant reaction that causes inflammation. Allergic patients often suffer from sneezing, itching/watery eyes, nasal stuffiness, and congestion. Less commonly symptoms may include scratchy sore throats, hoarseness, and cough. While allergies are rarely life threatening, they can lead to severe symptoms if secondary infections occur, and often lead to many days of missed work or school.
Many allergies are seasonal and vary depending upon the time of year. Ragweed (also called hayfever) is a major cause of allergies in the US and typically causes symptoms from late August until the first frost of the fall. Late springtime pollens often come from grasses, such as timothy, Bermuda, or some bluegrasses. Early springtime (late March or early April) pollens are more likely to be from trees, such as elm, oak, poplar, and walnut. Colorful, fragrant plants produce pollen that is too heavy to be carried in the wind and they rarely cause allergic reactions.
Other allergies are perennial and are present all year round. These include house dust, pet danders, foods, and molds. Symptoms may be worse in the winter because the house is closed up. Mold (or microscopic fungi) can grow in damp areas, both outdoors (around dead leaves or sheds/garages) and indoors (around house plants, bathrooms, or basements). Molds are most common in the warm, humid environment of the Southeastern US and are extremely light and easily carried on wind currents.
Redness and swelling (upper arm) typical with positive allergy test.
Allergy Prevention Techniques
- Wear a mask when exposed to significant irritants, such as mowing grass or house cleaning.
- Change heating and air conditioning air filters monthly.
- Install an air purifier.
- Keep the humidity in your house around 35 percent. Consider a humidifier in the dry winter months and air conditioners or dehumidifiers in the summer. Clean these appliances regularly to avoid mold growth.
- Keep windows and doors closed during allergy season with high pollen levels.
- Remove household plants and other sources of mold and mildew.
- Keep dander producing animals, such as cats, and dogs, outside.
- Change feather pillows and wool bedding to cotton or synthetic materials.
- Enclose pillows, mattresses, and box springs in plastic barrier cloth.
- Sleep with head of bed elevated to relieve nasal congestion.
Medical Therapy For Allergies
- Topical nasal steroids are very useful in most cases of allergic rhinitis and/or chronic sinusitis. They reduce the inflammation in the lining of the nose and sinuses with very few side effects. Some patients may experience minor nose bleeds from time to time, but these medications are generally very well-tolerated.
- Antihistamines can be very useful in patients with documented environmental allergies. As part of the body’s inflammatory response to allergies, a chemical called histamine is released. Histamine is responsible for congestion, sneezing, and runny nose, and antihistamines are able to block many of these reactions. For best results, they should be taken well in advance of an allergic attack. While newer generation antihistamines have fewer side effects than previous generations, they still may cause thickening of secretions in the nose and mouth, drowsiness, urinary retention, and constipation, thus non-allergic patients should probably refrain from using them.
- Oral and topical decongestants are generally prescribed on an as-needed basis. Histamine and other inflammatory chemicals cause blood vessels to dilate and lead to nasal congestion. Decongestants counteract this effect by causing contraction of the blood vessels in the nose and sinuses and opening the air passages. Short term (3-5 days) use may alleviate some of the symptoms of congestion and nasal obstruction seen in sinusitis. There is the potential for side effects, such as high blood pressure, hyperactivity, insomnia, and recurrent nasal congestion, with long-term use.
- Immunotherapy (traditionally given as shots) are also useful for patients with proven allergies. Patients require weekly shots for the first year and a tapering schedule after that, but the shots may provide patients with significant long-term relief without the need for chronic medications. The idea behind allergy shots is to stimulate blocking antibodies and develop permanent tolerance for the offending environmental trigger. It may take a few months for the shots to become effective, but over 80 percent of patients experience significant improvement in their symptoms. Immunotherapy can also be given as drops under the tongue, called SubLingual ImmunoTherapy (SLIT). This technique has been used in Europe since the mid 1980’s and is gaining popularity in the US. We have used SLIT at MUSC since 2007. Immunotherapy offers the only potential “cure” for allergies.