- Hay fever
DiseaseDisorder infobox
Name = Hay fever
Caption =Pollen grains from a variety of common plants can cause "hay fever".
DiseasesDB = 31140
ICD10 = ICD10|J|30|1|j|30
ICD9 = ICD9|477
OMIM = 607154
MedlinePlus = 000813
eMedicineSubj = ent
eMedicineTopic= 194
eMedicine_mult= eMedicine2|med|104 eMedicine2|ped|2560
MeshID = D006255Allergic rhinitis, known as hay fever, is caused by
pollen s of specific seasonal plants, airborne chemicals and dust particles in people who areallergic to these substances. Around 20% of Australians suffer from this.fact|date=September 2008 It is characterised by sneezing, runny nose and itching eyes. This seasonal allergicrhinitis is commonly known as 'hay fever', because it is most prevalent duringhay ing season. It is particularly prevalent from late May to the end of June (in the Northern Hemisphere). However, it is possible to suffer from hay fever throughout the year.Causes
Hay fever involves an
allergic reaction topollen . A virtually identical reaction occurs with allergy to mold, animaldander , dust and similar inhaled allergens. Particulate matter in polluted air and chemicals such as chlorine and detergents, which can normally be tolerated, can greatly aggravate the condition.The pollen that cause hay fever vary from person to person and from region to region; generally speaking, the tiny, hardly visible pollens of wind-pollinated
plant s 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:
* Trees: such as birch (Betula ), alder (Alnus ), cedar (Cedrus ), hazel (Corylus ), hornbeam (Carpinus ), horse chestnut (Aesculus ), willow (Salix ),poplar (Populus), 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.
* Grasses (FamilyPoaceae ): especiallyryegrass (Lolium sp.) and 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 ) andsorrel /dock (Rumex )In addition to individual sensitivity and geographic differences in local plant populations, the amount of pollen in the air can be a factor in whether hay fever symptoms develop. Hot, dry, windy days are more likely to have increased amounts of pollen in the air than cool, damp, rainy days when most pollen is washed to the ground.
The time of year at which hay fever symptoms manifest themselves varies greatly depending on the types of pollen to which an allergic reaction is produced. The pollen count, in general, is highest from mid-spring to early summer. As most pollens are produced at fixed periods in the year, a long-term hay fever sufferer may also be able to anticipate when the symptoms are most likely to begin and end, although this may be complicated by an allergy to dust particles.
When an allergen such as pollen or dust is inhaled by a person with a sensitized immune system, it triggers
antibody production. These antibodies mostly bind tomast cells , which containhistamine . When the mast cells are stimulated by pollen and dust, histamine (and other chemicals) are released. This causes itching, swelling, andmucus production. Symptoms vary in severity from person to person. Very sensitive individuals can experiencehives or otherrash es.Some disorders may be associated with allergies: Comorbidities include
eczema ,asthma ,depression andmigraine . [cite web | url=http://www.acaai.org/public/linkpages/NR+Rising+Prevalence+and+Unmet+Needs+of+Allergic+Rhinitis.htm | title=Allergists Explore Rising Prevalence and Unmet Needs Attributed to Allergic Rhinitis | date=November 12, 2006 | publisher=ACAAI | accessdate=2008-10-01]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.
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. [cite web|url=http://www.rush.edu/rumc/page-1098987384061.html|title=Rush University Medical Center|accessdate=2008-03-05]igns and tests
The history of the person's symptoms is important in diagnosing allergic
rhinitis , including whether the symptoms vary according to time of day or the season, exposure to pets or other allergens, and diet changes.Allergy testing may reveal the specific allergens the person is reacting 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.Sufferers might also find that cross-reactivity occurs. [cite journal |author=Czaja-Bulsa G, Bachórska J |title= [Food allergy in children with pollinosis in the Western sea coast region] |journal=Pol Merkur Lekarski |volume=5 |issue=30 |pages=338–40 |year=1998 |pmid=10101519] For example, someone allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes. [cite journal |author=Yamamoto T, Asakura K, Shirasaki H, Himi T, Ogasawara H, Narita S, Kataura A |title= [Relationship between pollen allergy and oral allergy syndrome] |journal=Nippon Jibiinkoka Gakkai Kaiho |volume=108 |issue=10 |pages=971–9 |year=2005 |pmid=16285612] 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. [cite journal |author=Malandain H |title= [Allergies associated with both food and pollen] |journal=Allerg Immunol (Paris) |volume=35 |issue=7 |pages=253–6 |year=2003 |pmid=14626714] There are many cross-reacting substances.
Treatment and Prevention
The goal of treatment is to reduce allergy symptoms caused by the inflammation of affected tissues. Prevention i.e. avoiding exposure to pollen is the best way to decrease allergic symptoms. [cite web | url=http://healthlink.mcw.edu/article/1031002426.html | title=The Facts about Hay Fever | accessdate=2007-06-19 | work=Healthlink | publisher=University of Wisconsin] [ cite web |url=http://www.nhs.uk/Conditions/Hay-fever/Pages/Prevention.aspx?url=Pages/Lifestyle.aspx | title = NHS advice on hayfever ]
Prevention
The following may be recommended as forms of prevention.
*Nasal irrigation with a Neti pot, which soothes cleans the sinuses of both mucous and allergens, also effectively doing the same for the tear ducts.
* Remaining indoors in the morning and evening when outdoor pollen levels are highest.
* Avoiding fields, large areas of grassland, and trips to rural areas. Trips to the seaside may be recommended instead as the sea breeze blows pollen inland.
* Avoiding mowing the grass or doing other outdoor work, if possible.
* Wearing face masks designed to filter out pollen when outdoors (including walking or cycling).
* Keeping windows closed and using theair conditioner in the house and car. A pollen filter can be fitted to cars.
* Not drying clothes outdoors.
* Avoiding unnecessary exposure to other environmental irritants such as insect sprays,tobacco smoke,air pollution , and fresh tar or paint.
* Regular hand and face-washing removes pollen from areas where it is likely to enter the nose.
* Regular hair washing before going to bed removes pollen so it doesn't get stuck onto the pillow.
* A small amount of petroleum jelly around the eyes and nostrils may stop some pollen from entering the areas that cause a reaction
* Wearing wrap-around sunglasses, which reduce the amount of pollen entering the eyes. Wearing hypo-allergenic eye makeup and avoiding rubbing the eyes. Wearing goggles while swimming.
* Taking a shower before going to bed and changing bed linen often to avoid extra exposure during the nightMedication
The most appropriate medication depends on the type and severity of symptoms. Specific illnesses that are caused by allergies (such as asthma and eczema) may require other treatments.
Options include the following:
ystemic therapy
Therapies that have an overall effect on a person's body and therefore thay may help for all of the symptoms include: ;
Antihistamine s: these are taken by mouth and may relieve mild to moderate symptoms. The first-generation (non-selective or classical) antihistamines such aschlorphenamine andpromethazine are perhaps the most effective, but their sedative side effects limits their usefulness compared to the newer second-generation and third-generation (selective, non-sedating) antihistamines such asloratadine andcetirizine . Most of these antihistamines are available asover-the-counter drug s.;Glucocorticoid s:Corticosteroid s administered to the whole body, such asTriamcinolone (Kenalog) byintramuscular injection , are also effective, but their use is limited by their short duration of effect, lasting a few weeks, and the side effects of prolonged steroid therapy. ;Leukotriene receptor antagonists: these newer products, such asmontelukast (Singulair) andzafirlukast (Accolate), have proven very effective in dealing with allergic rhinitis, without the common side-effects of the first-generation antihistamines, such as drowsiness. These medicines are also long-acting and are taken once-daily.Topical therapy
Localised treatments may give more effective relief of eye or nasal symptoms.
Nasal treatments
; Steroid
nasal spray s: are effective and safe, and may be effective without oral antihistamines. These medications include, in order of potency:beclomethasone (Beconase),budesonide (Rhinocort),flunisolide (Syntaris), mometasone (Nasonex),fluticasone (Flonase, Flixonase),triamcinolone (Nasacort AQ). They take several days to act and so need be taken continually for several weeks as their therapeutic effect builds up with time.;Cromoglicate : is a drug that stabilizesmast cells to prevent their degranulation and subsequent release of histamine. It is available as a nasal spray (Nasalcrom) for treating hay fever, although it is generally less effective than nasal steroid sprays.; Antihistamine:Azelastine (Astelin) is the only antihistamine available as a nasal spray.;Topical decongestant s: 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 ).; Saltwater sprays, rinses or steam: this removes dust, secretions and allergenic molecules from the mucosa, as they are all instant water soluble. A suitable solution is 2-3 spoonful of salt dissolved in one litre of lukewarm water. [ url = http://www.allergy.org.au/aer/infobulletins/hayfever_treatment.htm | Australian Society of Clinical Immunology and Allergy]Eye treatments
; Cromoglicate: is also used as eye drops (Crolom in US and Opticrom in UK being best known brands).
Nedocromil is a newer variant of cromoglycate and has essentially the same activity.Allergy immunotherapy
Allergy immunotherapy is commonly used in patients suffering from allergicrhinitis , allergicasthma , or life threatening stinging insect allergy. This type of therapy has been found to potentially alter the course of all three of the above disorders. Allergen immunotherapy provides long-term relief of the symptoms associated with rhinitis and asthma."Allergy shots" (
Hyposensibilization ,immunotherapy ) are occasionally recommended if the allergen cannot be avoided and if symptoms are hard to control. This includes regular injections of the allergen, given in increasing doses, which may help the body adjust to the antigen. These tend to be offered as a last resort as the therapy is more expensive at first, although patients may save money on medications and doctor visits in the long run. They may also increase the risk of triggering a secondary allergic reaction such as an asthma attack.Allergy shot treatment is the closest thing to a ‘cure’ for allergic symptoms. This therapy requires a long-term commitment.
Herbal treatments
A large number of over-the-counter treatments are sold without FDA approval, including
herbs likeeyebright ("Euphrasia officinalis"),nettle ("Urtica dioica"), andbayberry ("Myrica cerifera"), which have not been shown to reduce the symptoms of nasal-pharynx congestion. In addition,feverfew ("Tanacetum parthenium") andturmeric ("Curcuma longa") has been shown to inhibit phospholipase A2, the enzyme which releases the inflammatory precursorarachidonic acid from the bi-layer membrane ofmast cells (the main cells which respond to respiratory allergens and lead to inflammation) but this is only in test tubes and it is not established as anti-inflammatory in humans.Homeopathy
It has been claimed that
homeopathy provides relief free of side-effects. However, this is strongly disputed by the medical profession on the grounds that there is no valid evidence to support this claim. [cite web | url=http://www.york.ac.uk/inst/crd/ehc73.pdf | title=Effective Health Care: Homeopathy | accessdate=2007-06-10 | author=Susan O'Meara, Paul Wilson, Chris Bridle, Jos Kleijnen and Kath Wright | date=2002 | format=PDF | publisher=NHSCentre for Reviews and Dissemination | quote=There are currently insufficient data ... to recommend homeopathy as a treatment for any specific condition]Acupuncture
Therapeutic efficacy of complementary-alternative treatments for rhinitis and asthma is not supported by currently available evidence. [cite journal |author=Passalacqua G, Bousquet PJ, Carlsen KH, Kemp J, Lockey RF, Niggemann B, Pawankar R, Price D, Bousquet J |title=ARIA update: I--Systematic review of complementary and alternative medicine for rhinitis and asthma |journal=J. Allergy Clin. Immunol. |volume=117 |issue=5 |pages=1054–62 |year=2006 |pmid=16675332 |doi=10.1016/j.jaci.2005.12.1308] [cite journal | author =Terr A | title = Unproven and controversial forms of immunotherapy | journal = Clin Allergy Immunol. | volume = 18 | issue = 1 | pages = 703–10 | year = 2004 | pmid = 15042943]
Nevertheless, there have been some attempts with controlled trials [cite book | author=World Health Organisation| title=Acupuncture: Review and Analysis of Reports on Controlled Clinical Trials | journal=N Engl J Med | year=2002 | pages=87 | isbn=9789241545433] to show that
acupuncture is more effective than antihistamine drugs in treatment of hay fever. Complementary-alternative medicines such as acupuncture are extensively offered in the treatment of allergic rhinitis by non-physicians but evidence-based recommendations are lacking. The methodology of clinical trials with complementary-alternative medicine is frequently inadequate. Meta-analyses provides no clear evidence for the efficacy of acupuncture in rhinitis (or asthma). It is not possible to provide evidence-based recommendations for acupuncture or homeopathy in the treatment of allergic rhinitis.Honey
Eating locally produced unfiltered honey is believed by many to be a treatment for hayfever, supposedly by introducing manageable amounts of pollen to the body. Clinical studies have not provided any evidence for this belief. [ (Furthermore, it should be noted that honeybees visit precisely those plants that are not pollinated by the wind and are, therefore, less likely to cause allergic rhinitis.) cite journal
quotes = This study does not confirm the widely held belief that honey relieves the symptoms of allergic rhinoconjunctivitis
author = TV Rajan, H Tennen, RL Lindquist, L Cohen, J Clive
year = 2002
month = February
title = Effect of ingestion of honey on symptoms of rhinoconjunctivitis
journal = Annals of allergy, asthma & immunology
volume = 88
issue = 2
pages = 198–203
issn = 1081-1206
pmid = 11868925
quote = This study does not confirm the widely held belief that honey relieves the symptoms of allergic rhinoconjunctivitis ]Expectations
Most symptoms of allergic rhinitis can be readily treated.
In some cases (particularly in children), people may outgrow an allergy as the immune system becomes less sensitive to the allergen. However, as a general rule, once a substance causes allergies for an individual, it can continue to affect the person over the long term.
More severe cases of allergic rhinitis require immunotherapy (allergy shots) or removal of tissue in the nose (e.g.,
nasal polyp s) or sinuses.Complications
*
drowsiness and other side effects ofantihistamines
* side-effects of othermedication s (see the specific medication)
*asthma
*sinusitis
*nasal polyps
* disruption of lifestyle (can be extensive)
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