- Rhinitis is simply inflammation of the nasal passages. Allergic rhinitis is inflammation of the nasal passages through an allergic mechanism. Allergic rhinitis can be seasonal, that is, occurring at certain times of the year or perennial, occurring throughout the year.
- The symptoms of allergic rhinitis are: sneezing, often paroxysmal ( a series of sneezes); rhinorrhea or runny nose, usually clear and colorless in allergy; itching of the nose with rubbing (the allergic salute); and stuffy obstructed nasal passages.
- Allergic rhinitis is often associated with allergic conjunctivitis in which the eyes itch, often tear, turn red with injected blood vessels and may even have swelling of the sclera (whites of the eyes) or puffiness around the lids. Rubbing at the eyes can lead to styes or infections in the eyelids or scratching of the corneas.
- Some people notice itching of the ears and even palate.
- The mechanism for the symptoms is well known. Allergic people (about 20 - 30% of the population) form a type of antibody (IgE) to the offending allergens. The IgE antibody sits on certain cells (mast cells and basophils) which contain granules of mediators especially histamine. When the allergen becomes bound by the IgE antibodies on the surface of these cells, it causes them to release their histamine and other mediators. Histamine released during this reaction causes dilatation of blood vessels which causes them to leak fluid. Histamine also creates itching. Moreover as the allergic reaction continues, other cells are called from the blood (eosinophils) that release other toxic granules that further inflame the surrounding tissue in a more long-lasting fashion.
- Thus the release of histamine into the nasal or eye tissue creates congestion of blood vessels, fluid formation and itching. The influx of eosinophils creates nasal congestion and obstruction of the nasal passages. The children tend to rub at their eyes and nose making things worse.
- If the offending allergens are year-round allergens such as dust mites or animal danders, the symptoms can occur throughout the year. If the allergens are seasonal such as tree, grass, ragweed or tree-leaf moulds, the symptoms will occur in the warmer months from spring to fall. The pollens and leaf moulds are wind-borne and carried over large areas in the air. In contrast, plants that pollinate through carriage by bees have heavier pollens that do not spread through the air and are not usually allergenic (e.g. Goldenrod).
- In Ontario, the common perennial allergens are animal danders, dust mites and indoor moulds. However dust mites require high humidity and in the winter when the furnace is on, the humidity in the home can fall very low. The mites then are unable to proliferate and the symptoms of allergic rhinitis can seem to be seasonal in the spring and fall. Usually symptoms of allergic rhinitis in the early spring (April) are due to tree pollen allergy.
- It is hard to avoid pollens but if the home is air-conditioned and set to circulate only indoor air while the windows are kept closed in the pollen season, the indoor environment will be kept pollen free. A similar strategy can be followed in the car if air-conditioning is available. Generally pollen counts are higher in the morning and are washed down on rainy days. It is recommended that outdoor activities be confined to later in the day but that is a restrictive strategy. Outdoor mould spores can be reduced in a similar fashion although mould spores may be higher on windy, wet days.
- The tree pollen season occurs in early spring from April through to June depending on the type of tree.
- The grass season begins slightly later in May through to July.
- The ragweed season begins in August and ends around October.
- The mould season begins early in the spring and continues past the ragweed season.
- Treatment depends on an understanding of how the medications work. This discussion will be general and like any allopathic treatment regimen should be undertaken under the supervision of a physician.
- For Nasal symptoms: Oral antihistamines give rapid relief of histamine related symptoms such as itching, rhinorrhea and sneezing but do not work well for stuffiness which would require the addition of a decongestant. Oral decongestants may create an unpleasant sensation of shakiness. Topical decongestants can only be used for short periods of 4 - 5 days since "rebound" effects may occur. Topical nasal steroids will gradually reduce the stuffiness by reducing mucous and the inflammatory cells in the mucosa.
- For Eye symptoms: Oral antihistamines will block the itching and redness due to histamine release and if used topically [levocabastine (Livostin) or olopatadine (Patanol)], give rapid relief. Mast cell stabilizing agents such as cromoglycate (Opticrom, Cromolyn) or lodoxamide (Alomide) prevent release of histamine and other mediators from mast cells while gradually reducing cellular inflammation. Steroids are not used in the eyes on a routine basis. Lodoxamide seems to be slightly more potent than cromoglycate but the latter is available without prescription.
- If symptoms are severe enough to prevent sleep and disrupt day-time activities, a short course of oral steroid may be used to start symptom relief.
- If medications have been tried and have been found to give incomplete relief of symptoms or are too inconvenient to use regularly, a course of preseasonal immunotherapy can be administered finishing just prior to the onset of the pollen season. There are specific injections of each pollen that is, modified tree, grass and ragweed allergens.
- Side Effects of Treatment: PLEASE NOTE, This discussion is in general terms only. For a more complete discussion of adverse effects of these medication, one should read the package insert or consult a physician or pharmacist. Oral antihistamines are generally safe and the newer ones create less sedation. Because of their safety, they are available without prescription but like any medication should be used only at recommended doses and for limited times. Topical antihistamines for the eyes and nose are also generally safe but all topical agents contain preservatives which can be irritating when the eyes are inflamed. Topical steroids are generally safe when used as prescribed at the appropriate dose for limited time periods. The commonest complaint is over-drying the nasal mucosa and nose bleed.
Long term use of nasal steroids in high doses can lead to absorption and systemic side effects typical for steroid so that their use should be under the supervision of a physician. Oral steroid can be associated with significant side effects and as a result is only used in extreme circumatances under the supervision of a physician who will discuss potential side effects along with risks and benefits.
For a more humorous look at allergic rhinitis go to Mr. Nose and his Allergies. This animation only works with Microsoft Internet Explorer browsers version 5 and higher. Go to Mr. Nose
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