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==Classification==
==Classification==
The two categories of allergic [[rhinitis]] include:
The two categories of allergic [[rhinitis]] include:
* Seasonal—occurs particularly during pollen seasons. Seasonal allergic rhinitis does not usually develop until after 6 years of age who will do themselves after treatment.
* Seasonal—occurs particularly during pollen seasons. Seasonal allergic rhinitis does not usually develop until after 6 years of age.
* Perennial&mdash;occurs throughout the year. This type of allergic rhinitis is commonly seen in younger children.<ref>{{cite web|url=http://www.rush.edu/rumc/page-1098987384061.html|title=Rush University Medical Center|accessdate=2008-03-05}}</ref>
* Perennial&mdash;occurs throughout the year. This type of allergic rhinitis is commonly seen in younger children.<ref>{{cite web|url=http://www.rush.edu/rumc/page-1098987384061.html|title=Rush University Medical Center|accessdate=2008-03-05}}</ref>


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Allergic rhinitis triggered by the [[pollen]]s of specific seasonal plants is commonly known as "hay fever", because it is most prevalent during [[hay]]ing season. However, it is possible to suffer from hay fever throughout the year. The pollen which causes hay fever varies between individuals and from region to region; generally speaking, the tiny, hardly visible pollens of [[Anemophily|wind-pollinated]] [[plant]]s are the predominant cause. Pollens of [[entomophily|insect-pollinated]] plants are too large to remain airborne and pose no risk. Examples of plants commonly responsible for hay fever include:
Allergic rhinitis triggered by the [[pollen]]s of specific seasonal plants is commonly known as "hay fever", because it is most prevalent during [[hay]]ing season. However, it is possible to suffer from hay fever throughout the year. The pollen which causes hay fever varies between individuals and from region to region; generally speaking, the tiny, hardly visible pollens of [[Anemophily|wind-pollinated]] [[plant]]s are the predominant cause. Pollens of [[entomophily|insect-pollinated]] plants are too large to remain airborne and pose no risk. Examples of plants commonly responsible for hay fever include:
* Trees: such as pine, bitch (''[[Betula]]''), alder (''[[Alnus]]''), cedar, hazel, hornybeam (''[[Carpinus]]''), horsenuts (''[[Aesculus]]''), willow (''[[Salix]]''), [[poplar]], plane (''[[Platanus]]''), linden/lime (''[[Tilia]]'') and olive (''[[Olea]]''). In northern latitudes birch is considered to be the most important allergenic tree pollen, with an estimated 15–20% of hay fever sufferers sensitive to birch pollen grains. Olive pollen is most predominant in Mediterranean regions. [[Hay fever in Japan]] is caused primarily by [[sugi]] (''Cryptomeria japonica'') and [[hinoki]] (''Chamaecyparis obtusa'') tree pollen.
* Trees: such as pine, birch (''[[Betula]]''), alder (''[[Alnus]]''), cedar, hazel, hornbeam (''[[Carpinus]]''), horse chestnut (''[[Aesculus]]''), willow (''[[Salix]]''), [[poplar]], plane (''[[Platanus]]''), linden/lime (''[[Tilia]]'') and olive (''[[Olea]]''). In northern latitudes birch is considered to be the most important allergenic tree pollen, with an estimated 15–20% of hay fever sufferers sensitive to birch pollen grains. Olive pollen is most predominant in Mediterranean regions. [[Hay fever in Japan]] is caused primarily by [[sugi]] (''Cryptomeria japonica'') and [[hinoki]] (''Chamaecyparis obtusa'') tree pollen.
* Grasses (Family [[Poaceae]]): especially [[ryegrass]] (''Lolium'' sp.) and [[Timothy-grass|timothy]] (''Phleum pratense''). An estimated 90% of hay fever sufferers are allergic to grass pollen.
* Grasses (Family [[Poaceae]]): especially [[ryegrass]] (''Lolium'' sp.) and [[Timothy-grass|timothy]] (''Phleum pratense''). An estimated 90% of hay fever sufferers are allergic to grass pollen.
* Weeds: [[ragweed]] (''Ambrosia''), plantain (''[[Plantago]]''), [[nettle]]/parietaria ([[Urticaceae]]), [[mugwort]] (''Artemisia''), [[Fat hen]] (''[[Chenopodium]]'') and [[sorrel]]/dock (''[[Rumex]]'')
* Weeds: [[ragweed]] (''Ambrosia''), plantain (''[[Plantago]]''), [[nettle]]/parietaria ([[Urticaceae]]), [[mugwort]] (''Artemisia''), [[Fat hen]] (''[[Chenopodium]]'') and [[sorrel]]/dock (''[[Rumex]]'')

Revision as of 08:01, 16 July 2011

For the play, see Hay Fever.
Allergic rhinitis
SpecialtyImmunology Edit this on Wikidata

Allergic rhinitis, also known as pollenosis or hay fever, is an allergic inflammation of the nasal airways. It occurs when an allergen, such as pollen or dust, is inhaled by an individual with a sensitized immune system. In such individuals, the allergen triggers the production of the antibody immunoglobulin E (IgE), which binds to mast cells and basophils containing histamine.

IgE bound to mast cells are stimulated by pollen and dust, causing the release of inflammatory mediators such as histamine (and other chemicals).[1] This causes itching, swelling, and mucus production. Symptoms vary in severity between individuals. Very sensitive individuals can experience hives or other rashes. Particulate matter in polluted air, and chemicals such as chlorine and detergents, which can normally be tolerated, can greatly aggravate allergic rhinitis. The physician John Bostock first described hay fever in 1819 as a disease.

Classification

The two categories of allergic rhinitis include:

  • Seasonal—occurs particularly during pollen seasons. Seasonal allergic rhinitis does not usually develop until after 6 years of age.
  • Perennial—occurs throughout the year. This type of allergic rhinitis is commonly seen in younger children.[2]

Allergic rhinitis may also be classified as Mild-Intermittent, Moderate-Severe intermittent, Mild-Persistent, and Moderate-Severe Persistent. Intermittent is when the symptoms occur <4 days per week or <4 consecutive weeks. Persistent is when symptoms occur >4 days/week and >4 consecutive weeks. The symptoms are considered mild with normal sleep, no impairment of daily activities, no impairment of work or school, and if symptoms are not troublesome. Severe symptoms result in sleep disturbance, impairment of daily activities, and impairment of school or work. These symptoms may cause cough, cold or obstruction to respiratory passage while breathing.[3]

Signs and symptoms

The early phase of the reaction begins minutes after exposure causing vasodilation, increase vascular permeability, production of nasal secretions, rhinorrhea, itching, sneezing, nasal obstruction. The late phase of the reaction occurs 4–8 hours after exposure and mainly causes nasal congestion.[4]

Characteristic physical findings in individuals who have allergic rhinitis include conjunctival swelling and erythema, eyelid swelling, lower eyelid venous stasis, lateral crease on the nose, swollen nasal turbinates, and middle ear effusion.[5]

Sufferers might also find that cross-reactivity occurs.[6] For example, someone allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes.[7] A clear sign of this is the occurrence of an itchy throat after eating an apple or sneezing when peeling potatoes or apples. This occurs because of similarities in the proteins of the pollen and the food.[8] There are many cross-reacting substances.

Some disorders may be associated with allergies: Comorbidities include eczema, asthma, depression and migraine.[9]

Cause

Allergies are common. Heredity and environmental exposures may contribute to a predisposition to allergies. It is roughly estimated that one in three people have an active allergy at any given time and at least three in four people develop an allergic reaction at least once in their lives.

Allergic rhinitis triggered by the pollens of specific seasonal plants is commonly known as "hay fever", because it is most prevalent during haying season. However, it is possible to suffer from hay fever throughout the year. The pollen which causes hay fever varies between individuals and from region to region; generally speaking, the tiny, hardly visible pollens of wind-pollinated plants are the predominant cause. Pollens of insect-pollinated plants are too large to remain airborne and pose no risk. Examples of plants commonly responsible for hay fever include:

Allergy testing may reveal the specific allergens an individual is sensitive to. Skin testing is the most common method of allergy testing. This may include intradermal, scratch, patch, or other tests. Less commonly, the suspected allergen is dissolved and dropped onto the lower eyelid as a means of testing for allergies. (This test should only be done by a physician, never the patient, since it can be harmful if done improperly). In some individuals who cannot undergo skin testing (as determined by the doctor), the RAST blood test may be helpful in determining specific allergen sensitivity.

Management

The goal of rhinitis treatment is to prevent or reduce the symptoms caused by the inflammation of affected tissues. In cases of allergic rhinitis, the most effective way to decrease allergic symptoms is to completely avoid the allergen.[10][11] Vasomotor rhinitis can be brought under a measure of control through avoidance of irritants, though many irritants, such as weather changes, are uncontrollable.

Allergic rhinitis can typically be treated much like any other allergic condition. Eliminating exposure to allergens is the most effective preventive measure, but requires consistent effort. Many people with pollen allergies reduce their exposure by remaining indoors during hay fever season, particularly in the morning and evening, when outdoor pollen levels are at their highest. Closing all the windows and doors prevents wind-borne pollen from entering the home or office. When traveling in a vehicle, closing all the windows reduces exposure. Air conditioners are reasonably effective filters, and special pollen filters can be fitted to both home and vehicle air conditioning systems.[12]

Rinsing is very often recommended as part of the healing process after sinus or nasal surgery. For this rinse, boiled or distilled water is only necessary during recovery from surgery, as the entire contents of the bottle is used.[13]

Receptor antagonists (including antihistamines)

Several antagonistic drugs are used to block the action of allergic mediators, or to prevent activation of cells and degranulation processes. These include antihistamines, cortisone, dexamethasone, hydrocortisone, epinephrine (adrenaline), theophylline and cromolyn sodium. Anti-leukotrienes, such as montelukast, are FDA approved for treatment of allergic diseases.[14] One antihistamine, azelastine, is available as a nasal spray.

Antihistamine drugs can have undesirable side-effects, most notably drowsiness. First generation antihistamine drugs such as diphenhydramine cause drowsiness, but not second- and third-generation antihistamines such as cetirizine and loratadine.[15]

Antihistamine drugs can be taken orally to control symptoms such as sneezing, rhinorrhea, itching and conjunctivitis. It is best to take the medication before exposure, especially for seasonal allergic rhinitis. Ophthalmic antihistamines (such as ketotifen) are used for conjunctivitis; intranasal forms are used for sneezing, rhinorrhea and nasal pruritus.[15]

A case-control study found "symptomatic allergic rhinitis and rhinitis medication use are associated with a significantly increased risk of unexpectedly dropping a grade in summer examinations".[16]

Another study “suggests that drivers who need antihistamine drugs should avoid those that act centrally” because they “greatly impaired driving behaviour”. [17]

Steroids

Systemic steroids such as prednisone are effective at reducing nasal inflammation, but their use is limited by their short duration of effect and the side effects of prolonged steroid therapy. Steroid nasal sprays are effective and safe, and may be effective without oral antihistamines. They take several days to act and so need be taken continually for several weeks as their therapeutic effect builds up with time.

Intranasal corticosteroids are used to control symptoms associated with sneezing, rhinorrhea, itching and nasal congestion. It is an excellent choice for perennial rhinitis.[18]

Decongestants

Pseudoephedrine is also indicated for vasomotor rhinitis. It is only used when nasal congestion is present and can be used with antihistamines. In the United States, oral decongestants containing pseudoephedrine must be purchased behind the pharmacy counter by law to combat the making of methamphetamine.[19]

Topical decongestants: may also be helpful in reducing symptoms such as nasal congestion, but should not be used for long periods as stopping them after protracted use can lead to a rebound nasal congestion (Rhinitis medicamentosa).

Combination treatments

For nocturnal symptoms, intranasal corticosteroids can be combined with nightly oxymetazoline, an adrenergic alpha-agonist, without risk of rhinitis medicamentosa.[20]

Desensitization

More severe cases of allergic rhinitis require Allergen immunotherapy (allergy shots) or removal of tissue in the nose (e.g., nasal polyps) or sinuses.

Alternative treatments

Therapeutic efficacy of complementary-alternative treatments is not supported by currently available evidence.[21][22] Some evidence shows that acupuncture is effective for rhinitis while other evidence does not. The overall quality of evidence, however, is poor.[23]

Epidemiology

In Western countries between 10–25% of people annually are affected by allergic rhinitis.[24]

References

  1. ^ May JR, Smith PH. Allergic Rhinitis. In: Dipiro JT, Talbert RL, Yee GC, et al eds.Pharmacotherapy: A Pathophysiologic Approach. 7th ed. New York, NY: The McGraw-Hill Companies, Inc; 2008:1565-1575.)
  2. ^ "Rush University Medical Center". Retrieved 2008-03-05.
  3. ^ Bousquet J, Reid J, van Weel C, et al. Allergic rhinitis management pocket reference 2008. Allergy 2008 Aug; 63 (8):990-996
  4. ^ Hansen I, Klimek L, Mosges R, Hormann K. Mediators of inflammation in the early and the late phase of allergic rhinitis. Curr Opin Allergy Clin Immunol. Jun 2004;4(3):159-63. [Medline]
  5. ^ Valet RS, Fahrenholz JM. Allergic rhinitis: update on diagnosis. Consultant. 2009;49:610-613
  6. ^ Czaja-Bulsa G, Bachórska J (1998). "[Food allergy in children with pollinosis in the Western sea coast region]". Pol Merkur Lekarski. 5 (30): 338–40. PMID 10101519.
  7. ^ Yamamoto T, Asakura K, Shirasaki H, Himi T, Ogasawara H, Narita S, Kataura A (2005). "[Relationship between pollen allergy and oral allergy syndrome]". Nippon Jibiinkoka Gakkai Kaiho. 108 (10): 971–9. PMID 16285612.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ Malandain H (2003). "[Allergies associated with both food and pollen]". Allerg Immunol (Paris). 35 (7): 253–6. PMID 14626714.
  9. ^ "Allergists Explore Rising Prevalence and Unmet Needs Attributed to Allergic Rhinitis". ACAAI. November 12, 2006. Retrieved 2008-10-01.
  10. ^ "The Facts about Hay Fever". Healthlink. University of Wisconsin. Retrieved 2007-06-19.
  11. ^ "NHS advice on hayfever".
  12. ^ Steven Jay Weiss. "Seasonal Allergic Rhinitis". Retrieved 2009-01-28.
  13. ^ Australian Society of Clinical Immunology and Allergy
  14. ^ eMedicine Health Hay Fever Causes, Symptoms, and Treatment on eMedicineHealth.com
  15. ^ a b May JR, Smith PH. Allergic Rhinitis. In: Dipiro JT, Talbert RL, Yee GC, et al eds.Pharmacotherapy: A Pathophysiologic Approach. 7th ed. New York, NY: The McGraw-HillCompanies, Inc; 2008:1565-1575.)
  16. ^ Walker S, Khan-Wasti S, Fletcher M, Cullinan P, Harris J, Sheikh A (2007). "Seasonal allergic rhinitis is associated with a detrimental effect on examination performance in United Kingdom teenagers: case-control study". J. Allergy Clin. Immunol. 120 (2): 381–7. doi:10.1016/j.jaci.2007.03.034. PMID 17560637.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  17. ^ T Betts, D Markman, S Debenham, D Mortiboy, and T McKevitt. "Effects of two antihistamine drugs on actual driving performance". Retrieved 1984-01-28. {{cite web}}: Check date values in: |accessdate= (help)CS1 maint: multiple names: authors list (link)
  18. ^ May JR, Smith PH. Allergic Rhinitis. In: Dipiro JT, Talbert RL, Yee GC, et al eds.Pharmacotherapy: A Pathophysiologic Approach. 7th ed. New York, NY: The McGraw-HillCompanies, Inc; 2008:1565-1575.
  19. ^ May JR, Smith PH. Allergic Rhinitis. In: Dipiro JT, Talbert RL, Yee GC, et al eds.Pharmacotherapy: A Pathophysiologic Approach. 7th ed. New York, NY: The McGraw-HillCompanies, Inc; 2008:1565-1575
  20. ^ Baroody FM, Brown D, Gavanescu L, Detineo M, Naclerio RM (2011). "Oxymetazoline adds to the effectiveness of fluticasone furoate in the treatment of perennial allergic rhinitis". J Allergy Clin Immunol. 127 (4): 927–34. doi:10.1016/j.jaci.2011.01.037. PMID 21377716.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  21. ^ Passalacqua G, Bousquet PJ, Carlsen KH, Kemp J, Lockey RF, Niggemann B, Pawankar R, Price D, Bousquet J (2006). "ARIA update: I--Systematic review of complementary and alternative medicine for rhinitis and asthma". J. Allergy Clin. Immunol. 117 (5): 1054–62. doi:10.1016/j.jaci.2005.12.1308. PMID 16675332.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  22. ^ Terr A (2004). "Unproven and controversial forms of immunotherapy". Clin Allergy Immunol. 18 (1): 703–10. PMID 15042943.
  23. ^ Witt CM, Brinkhaus B (2010). "Efficacy, effectiveness and cost-effectiveness of acupuncture for allergic rhinitis - An overview about previous and ongoing studies". Auton Neurosci. doi:10.1016/j.autneu.2010.06.006. PMID 20609633. {{cite journal}}: Unknown parameter |month= ignored (help)
  24. ^ Dykewicz MS, Hamilos DL (2010). "Rhinitis and sinusitis". J. Allergy Clin. Immunol. 125 (2 Suppl 2): S103–15. doi:10.1016/j.jaci.2009.12.989. PMID 20176255. {{cite journal}}: Unknown parameter |month= ignored (help)
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