Allergic Rhinitis and Its Causes
Allergic rhinitis is an atopic disease, which is inherited from the parent. If both your parents have allergic rhinitis or other respiratory diseases such as asthma, tuberculosis, and emphysema, the probability that you have these kinds of respiratory diseases is 50%. If one of your parents has respiratory diseases, the probability that you inherit their diseases is 25%. If both of your parents do not have any respiratory diseases, your chances to have respiratory diseases are no more than 12.5%. Sometimes, what has happened during pregnancy can cause allergic rhinitis to the newly born baby. The immunological status of the mother during pregnancy may cause the newly born baby has allergic rhinitis. Pregnant mothers who are smoking, drinking coffee and alcohol usually have poor immunological status, which can also cause newly born infant has allergic rhinitis or other respiratory diseases. This is because all these acts can cause high IgE antibody level in umbilical blood. Apart that, using bottle-feeding to feed milk to infant, early introduction of several kinds of food and early exposure to certain allergens and pollutants can cause nasal allergy to the newly born infant.
Allergic rhinitis symptoms change with age. At the earlier stage, children are mostly sensitive to seasonal allergens. After they have grown older, they usually become sensitive to perennial allergens. Therefore, after they have got over the symptom that is caused by seasonal allergens, they may still keep on the symptoms due to the perennial allergens. When the children grow older, they may have higher risk to have bronchial hyperreactivity and asthma. 17 to 19% of them will have asthma after grow up. To protect them from getting asthma, perennial immunotherapy should be used at the early stage. Moreover, the risk of getting asthma does not depend to age when the allergic rhinitis started, family history of atopic disease, sex, severity of symptoms at the starting period and treatment.
Allergic rhinitis started when the atopic individual meets the antigens that are able to stimulate the IgE response. So, what are substances that can act as allergens? Allergens usually are airborne particles, which have molecular weight ranging from 30 to 40,000 daltons and also with diameter ranging from 2 to 60 µm. Most of them have diameter more than 15 µm, which can deposit onto the nasal, pharyngeal and ocular surface. Chemically, these particles are proteins, which link to some small unit of carbohydrate. Particles that have these kinds of characters are pollen, acarids, animal dandruff and fungi.
Pollens that are released from grams, weeds and trees during breeding season usually cause seasonal allergic rhinitis. Only light pollens that can be pollinated by wind can exist in air and cause a high natural exposure to the allergic rhinitis patient. The seriousness depends to the concentration of the pollens in the atmosphere. Individual with allergic rhinitis who lives in suburban area will be seriously affected by these seasonal pollens compared to the one who lives in city. Surrounding temperature also gives an impact to the pollens concentration in air. Usually, in warmer environment, plants release more pollens compared to cold environment. Most of the plants breed in late spring and summer that is the warmest season. Windy weather will cause the pollens scatter around in air and this will cause the most exposure to the allergic rhinitis patient. The better day is rainy day. Rain water can wash all the pollens in air and bring them down to the ground. Surrounding air becomes fresher and cleaner after raining.
The main culprit of the perennial nasal allergy is house-dust mites. The acarids that are commonly found in the house dust are Dermatophagoides pteronyssimus and farinae, Euroglyphus maynei and Blomia tropicalis. Substances that are directly responsible to the nasal allergy from these dust mites are their body and metabolic products. Usually, mites grow rapidly in damp and warm climate. Therefore, sensitization to acarids depends to where you are actually living. Nasal allergy for patients who live in tropical and equatorial regions have higher possibility causes by acarids because these regions climate is promote mites growth. House-dust mites grow at maximized concentration when surrounding humidity level is between 70 to 80 % and with the presence of high temperature. Nasal allergy symptoms will develop when the level of dust mite concentration reaches 2 µg/g in air. Conversely, in high mountains with dry and cold climate have lowest level of dust mites because this climate prevents the mite growth. Animals also are the other source of aeroallergens. These aeroallergens are present in the animal’s saliva, feces, urine and dandruff. Therefore, nasal allergy can be caused by domestic animals such as cat and dog and also wild rats and mice.
Air pollutants enhance the sensitization of the nasal allergy by the allergens. Air pollutants can be divided to two groups that are outdoor pollutants, which are released from industrial works, automobile exhaust and domestic heating, and indoor pollutants such as tobacco smoke, furnishings, wood and coal burning and heater. Chemically, air pollutants consist of oxides of nitrogen, sulfur dioxide, ozone, carbon monoxide and black smoke. How actually air pollutants enhance sensitization of nasal allergy is not completely clear. This may be due to air pollutants easily irritate the respiratory mucosa and make it prone to allergic sensitization. Air pollutants have negative impact to the nasal epithelium and ciliary beat, which are responsible to the clearance of allergens. Furthermore, some pollutants can enhance the releasing of the mediators that induce inflammation such as histamine, prostaglandins and leukotriene C-4.
Apart from that, some pollutants also can stimulate synthesis of the IgE antibody directly. When allergen binds two IgE molecules together on the mast and basophil cells surface, primary chemical mediator; histamine, will be released and it will cause nasal allergy. Therefore, we can affirm that allergens can easily enter into our blood stream through our nasal mucosal membrane if we have chronic inflammation, not enough IgA antibody, impaired ciliary beat and also with air pollutants around us. IgA antibody is very important to our body because it prevents allergens from penetrating through our nasal mucosal layer. Monounsaturated oleic acids, which can be found in cold-pressed extra virgin olive and coconut oil, hazelnut or filbert oil (or the whole nuts), green and ripe olives, and almonds can increase IgA antibody in our body. Besides oleic acids, vitamin A also can increase IgA antibody, which can be found in cod liver oil, pumpkin, cooked carrots, sweet potatoes/yams, squash and other yellow or orange vegetable.
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