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| | {{Allergic conjunctivitis}} |
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| {{SI}} | | {{CMG}} {{AE}} {{Sujaya}} |
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| ==Overview==
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| '''Allergic [[conjunctivitis]]''' is [[Allergic Inflammation|inflammation]] of the [[conjunctiva]] (the membrane covering the white part of the eye) due to [[allergy]].<ref name="Bielory">{{cite journal | author = Bielory L, Friedlaender MH | title = Allergic conjunctivitis | journal = Immunol Allergy Clin North Am | volume = 28 | issue = 1 | pages = 43–58, vi | year = 2008 | month = February | pmid = 18282545 | doi = 10.1016/j.iac.2007.12.005 }}</ref> Although [[allergen]]s differ between patients, the most common cause is [[hay fever]]. Symptoms consist of redness (mainly due to [[vasodilation]] of the peripheral small blood vessels), [[oedema]] of the conjunctiva, [[itch]]ing and increased [[lacrimation]] (production of [[tears]]). If this is combined with [[rhinitis]], the condition is termed '''allergic rhinoconjunctivitis'''.
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| The symptoms are due to release of [[histamine]] and other active substances by [[mast cell]]s, which stimulate dilation of blood vessels, irritate nerve endings and increase secretion of tears.
| | {{SK}} [[Conjunctivitis]] - [[allergic]] seasonal; [[conjunctivitis]] - perennial; [[atopic]] [[keratoconjunctivitis]]; [[vernal]] [[keratoconjunctivitis]] |
| | ==[[Allergic conjunctivitis overview|Overview]]== |
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| Treatment of allergic conjunctivitis is by avoiding the allergen (e.g. avoiding grass in bloom during the "hay fever season") and treatment with [[antihistamine]]s, either topical (in the form of [[eye drop]]s), or systemic (in the form of tablets). Antihistamines, medication that stabilizes mast cells, and [[non-steroidal anti-inflammatory drugs]] (NSAIDs) are safe and usually effective.<ref name="Ono"/>
| | ==[[Allergic conjunctivitis historical perspective|Historical Perspective]]== |
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| ==Signs and symptoms== | | ==[[Allergic conjunctivitis classification|Classification]]== |
| The [[conjunctiva]] is a thin membrane that covers the eye. When an allergen irritates the conjunctiva, common symptoms that occur in the eye include: ocular itching, eyelid swelling, tearing, photophobia, watery discharge, and foreign body sensation (with pain).<ref name= "Bielory"/><ref name="Cunningham">{{cite journal | author = Whitcup SM | title = Recent advances in ocular therapeutics | journal = Int Ophthalmol Clin | editor = Cunningham ET Jr, Ng EWM | volume = 46 | issue = 4 | pages = 1–6 | year = 2006 | pmid = 17060786 | doi = 10.1097/01.iio.0000212140.70051.33 }}</ref>
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| Itching is the most typical symptom of ocular allergy and more than 75% of patients report this symptom when seeking treatment.<ref name= "Cunningham"/>
| | ==[[Allergic conjunctivitis pathophysiology|Pathophysiology]]== |
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| Symptoms are usually worse for patients when the weather is warm and dry, whereas cooler temperatures and rain tend to assuage symptoms.<ref name= "Bielory"/>
| | ==[[Allergic conjunctivitis causes|Causes]]== |
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| A study by Klein et al. showed that in addition to the physical discomfort allergic conjunctivitis causes, it also alters patients' routines, with patients limiting certain activities such as going outdoors, reading, sleeping, and driving.<ref name= "Cunningham"/> Therefore, treating patients with allergic conjunctivitis may improve their everyday "[[quality of life]]."
| | ==[[Allergic conjunctivitis differential diagnosis|Differentiating Allergic Conjunctivitis from other Diseases]]== |
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| Signs in PKC include small yellow nodules that develop over the cornea, which ulcerate after a few days.<ref name="ReferenceA">{{cite book |author=Allansmith M.R., Ross R.N. |chapter=Phlyctenular keratoconjunctivitis |editor=Tasman W., Jaeger E.A., |title=Duane's Clinical Ophthalmology |publisher=Harper & Row |location=Philadelphia |year=1991 |pages=1–5 |edition=revised |volume=1}}</ref>
| | ==[[Allergic conjunctivitis epidemiology and demographics|Epidemiology and Demographics]]== |
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| ==Causes== | | ==[[Allergic conjunctivitis risk factors|Risk Factors]]== |
| [[Image:01-09-11 0222.jpg|thumb|right|[[Human eye|Eye]] with allergic conjunctivitis]] | |
| The cause of allergic conjunctivitis is an [[allergic]] reaction of the body's immune system to an [[allergen]]. Allergic conjunctivitis is common in people who have other signs of allergic disease such as hay fever, asthma and eczema.<ref name="NetDoc">{{cite web|url=http://www.netdoctor.co.uk/diseases/facts/conjunctivitis.htm |title=Conjunctivitis (inflammation of the eye) |publisher=netdoctor.co.uk |accessdate=2010-04-06| archiveurl= http://web.archive.org/web/20100415200539/http://www.netdoctor.co.uk/diseases/facts/conjunctivitis.htm| archivedate= 15 April 2010 <!--DASHBot-->| deadurl= no}}</ref>
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| Among the most common allergens that cause conjunctivitis are:
| | ==[[Allergic conjunctivitis natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| * [[Pollen]] from trees, grass and ragweed
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| * Animal skin and secretions such as [[saliva]]
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| * [[Perfumes]]
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| * [[Cosmetics]]
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| * Skin medicines
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| * [[Air pollution]]
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| * [[Smoke]]<ref name="FD">{{cite web|url=http://familydoctor.org/online/famdocen/home/common/allergies/basics/678.html |title=Allergic Conjunctivitis |publisher=familydoctor.org |accessdate=2010-04-06}}</ref>
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| * [[Dust mites]]
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| * Eye drops<ref name="MedNews">{{cite web|url=http://www.medicalnewstoday.com/articles/157692.php |title=What Is Allergic Conjunctivitis? What Causes Allergic Conjunctivitis? |publisher=medicalnewstoday.com |accessdate=2010-04-06}}</ref>
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| Most cases of seasonal conjunctivitis are due to [[pollen]] and occur in the hay fever season, grass pollens in early summer and various other pollens and [[moulds]] may cause symptoms later in the summer.<ref name="PatUK">{{cite web|url=http://www.patient.co.uk/health/Allergic-Conjunctivitis.htm |title=What is conjunctivitis? |publisher=patient.co.uk |accessdate=2010-04-06| archiveurl= http://web.archive.org/web/20100430232351/http://www.patient.co.uk/health/Allergic-Conjunctivitis.htm| archivedate= 30 April 2010 <!--DASHBot-->| deadurl= no}}</ref>
| | ==Diagnosis== |
| | | [[Allergic conjunctivitis history and symptoms|History and Symptoms]] | [[Allergic conjunctivitis physical examination|Physical Examination]] | [[Allergic conjunctivitis laboratory findings|Laboratory Findings]] | [[Allergic conjunctivitis other diagnostic studies|Other Diagnostic Studies]] |
| Perennial conjunctivitis is commonly due to an allergy to house dust mite (a tiny insect-like creature that lives in every home).
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| Giant papillary conjunctivitis is a very rare condition that is mainly caused by an allergic reaction to "[[debris]]". Surgery may also cause this type of allergic conjunctivitis.
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| Contact dermatoconjunctivitis is caused by the rest of the allergens that conjunctiva may come into contact with: cosmetics, medications and so on.
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| ==Pathophysiology==
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| The ocular allergic response is a cascade of events that is coordinated by [[mast cells]].<ref>{{cite journal | author = Liu G, Keane-Myers A, Miyazaki D, Tai A, Ono SJ | title = Molecular and cellular aspects of allergic conjunctivitis | journal = Chem. Immunol. | volume = 73 | pages = 39–58 | year = 1999 | pmid = 10590573 | doi = 10.1159/000058748 | series = Chemical Immunology and Allergy | isbn = 3-8055-6893-2 }}</ref> Beta [[chemokine]]s such as [[eotaxin]] and [[CCL3|MIP-1 alpha]] have been implicated in the priming and activation of mast cells in the ocular surface. When a particular allergen is present, sensitization takes place and prepares the system to launch an antigen specific response. [[T helper cell|TH2 differentiated]] [[T cell]]s release cytokines, which promote the production of antigen specific [[immunoglobulin E]] (IgE). IgE then binds to IgE receptors on the surface of mast cells. Then, mast cells release [[histamine]], which then leads to the release of cytokines, [[prostaglandin]]s, and [[platelet-activating factor]]. Mast cell intermediaries cause an allergic inflammation and symptoms through the activation of inflammatory cells.<ref name= "Cunningham"/>
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| When [[histamine]] is released from mast cells, it binds to [[histamine H1 receptor|H1 receptors]] on nerve endings and causes the ocular symptom of itching. Histamine also binds to H1 and [[histamine H2 receptor|H2 receptors]] of the conjunctival vasculature and causes [[vasodilatation]]. Mast cell-derived cytokines such as chemokine interleukin [[Interleukin 8|IL-8]] are involved in recruitment of [[neutrophil]]s. TH2 cytokines such as [[Interleukin 5|IL-5]] recruit eosinophils and [[Interleukin 4|IL-4]], [[Interleukin 6|IL-6]], and [[Interleukin 13|IL-13]], which promote increased sensitivity. Immediate symptoms are due to the molecular cascade. Encountering the allergen a patient is sensitive to leads to increased sensitation of the system and more powerful reactions. Advanced cases can progress to a state of chronic allergic inflammation.<ref name= "Cunningham"/>
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| ==Classification==
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| ===SAC and PAC===
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| Both seasonal allergic conjunctivitis and perennial allergic conjunctivitis are two acute allergic conjunctival disorders.<ref name="Ono">{{cite journal | author = Ono SJ, Abelson MB | title = Allergic conjunctivitis: update on pathophysiology and prospects for future treatment | journal = J. Allergy Clin. Immunol. | volume = 115 | issue = 1 | pages = 118–22 | year = 2005 | month = January | pmid = 15637556 | doi = 10.1016/j.jaci.2004.10.042 }}</ref> SAC is the most common ocular allergy.<ref name= "Bielory"/><ref name="Buckley">{{cite journal | author = Buckley RJ | title = Allergic eye disease—a clinical challenge | journal = Clin. Exp. Allergy | volume = 28 | issue =Suppl 6 | pages = 39–43 | year = 1998 | month = December | pmid = 9988434 | doi = 10.1046/j.1365-2222.1998.0280s6039.x }}</ref> Symptoms of the aforementioned ocular diseases include itching and pink to reddish eye(s).<ref name= "Ono"/> These two eye conditions are mediated by mast cells.<ref name= "Ono"/><ref name= "Buckley"/> Nonspecific measures to ameliorate symptoms include cold compresses, eyewashes with tear substitutes, and avoidance of allergens.<ref name= "Ono"/> Treatment consists of [[antihistamine]], [[mast cell stabilizer]]s, dual mechanism anti-allergen agents, or topical antihistamines.<ref name= "Ono"/> [[Corticosteroid]]s are another option, but, considering the side-effects of [[cataracts]] and increased [[intraocular pressure]], corticosteroids are reserved for more severe forms of allergic conjunctivitis such as vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC).<ref name= "Ono"/>
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| ===VKC and AKC===
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| Both [[vernal keratoconjunctivitis]] and atopic keratoconjunctivitis are chronic allergic diseases wherein eosinophils, conjunctival fibroblasts, epithelial cells, mast cells, and TH2 lymphocytes aggravate the biochemistry and histology of the [[conjunctiva]].<ref name= "Ono"/> VKC is a disease of childhood and is prevalent in males living in warm climates.<ref name= "Ono"/> AKC is frequently observed in males between the ages of 30 and 50.<ref name= "Ono"/> VKC and AKC can be treated by medications used to combat allergic conjunctivitis or the use of steroids.<ref name= "Ono"/>
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| ===Giant papillary conjunctivitis===
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| Giant papillary conjunctivitis is not a true ocular allergic reaction and is caused by repeated mechanical irritation of the conjunctiva.<ref name= "Ono"/> Repeated contact with the conjunctival surface caused by the use of contact lenses is associated with GPC.<ref name= "Buckley"/>
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| ===Phlyctenular keratoconjunctivitis===
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| PKC results from a hypersensitivity/inflammatory reaction to bacteria.
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| Common pathogens include [[Staph. aureus]], [[Mycobacterium tuberculosis]], [[Chlamydia (bacterium)|Chlamydia]] and [[Candida (genus)|Candida]].<ref name="ReferenceA"/>
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| ==Treatment== | | ==Treatment== |
| A detailed history allows physicians to determine whether the presenting symptoms are due to an allergen or another source. Diagnostic tests such as conjunctival scrapings to look for eosinophils are helpful in determining the cause of the allergic response.<ref name="Ono"/> Antihistamines, medication that stabilizes mast cells, and [[non-steroidal anti-inflammatory drugs]] (NSAIDs) are safe and usually effective.<ref name="Ono"/> Corticosteroids are reserved for more severe cases of ocular allergy disease, and their use should be monitored by an eye care physician due to possible side-effects.<ref name="Ono"/> When an allergen is identified, the patient should avoid the allergen as much as possible.<ref name="Buckley"/>
| | [[Allergic conjunctivitis medical therapy|Medical Therapy]] | [[Allergic conjunctivitis surgery|Surgery]] | [[Allergic conjunctivitis primary prevention|Primary Prevention]] | [[Allergic conjunctivitis secondary prevention|Secondary Prevention]] | [[Allergic conjunctivitis cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Allergic conjunctivitis future or investigational therapies|Future or Investigational Therapies]] |
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| If the allergen is encountered and the symptoms are mild, a [[cold compress]] can be used to provide relief. It is a quick and easy solution without using any medications. The cold temperature of the water will help to bring down swelling, as it would in a bruise or burn. In addition, there are many antihistamine medications available for purchase.
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| [[Mast cell]] stabilizers can help curing patients with allergic conjunctivitis when [[cold compress]] are no longer effective. They tend to have delayed results, but they have fewer side-effects than the other treatments and last much longer than those of [[antihistamines]]. Some patients are given an antihistamine at the same time so that there is some relief of symptoms before the mast cell stabilizers becomes effective. Doctors commonly prescribe [[lodoxamide]] and [[nedocromil]] as mast cell stabilizers, which come as eye drops. | |
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| A mast cell stabilizer is a class of non-steroid controller medicine that reduces the release of inflammation-causing chemicals from mast cells. They block a calcium channel essential for mast cell degranulation, stabilizing the cell, thus preventing the release of [[histamine]]. Decongestants may also be prescribed. Another common mast cell stabilizer that is used for treating allergic conjunctivitis is [[sodium cromoglicate]].
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| Antihistamine medications are frequently prescribed because they provide immediate relief from the itch and burning symptoms.
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| Dual-action medications are also prescribed frequently. Olopatadine (Patanol)<ref>{{cite journal |author=Rosenwasser LJ, O'Brien T, Weyne J |title=Mast cell stabilization and anti-histamine effects of olopatadine ophthalmic solution: a review of pre-clinical and clinical research |journal=Curr Med Res Opin |volume=21 |issue=9 |pages=1377–87 |year=2005 |month=September |pmid=16197656 |doi=10.1185/030079905X56547 |url=http://informahealthcare.com/doi/abs/10.1185/030079905X56547}}</ref> and Ketotifen Fumarate (Alaway or Zaditor)<ref>{{cite journal |author=Avunduk AM, Tekelioglu Y, Turk A, Akyol N |title=Comparison of the effects of ketotifen fumarate 0.025% and olopatadine HCl 0.1% ophthalmic solutions in seasonal allergic conjunctivities: a 30-day, randomized, double-masked, artificial tear substitute-controlled trial |journal=Clin Ther |volume=27 |issue=9 |pages=1392–402 |year=2005 |month=September |pmid=16291412 |doi=10.1016/j.clinthera.2005.09.013 |url=http://linkinghub.elsevier.com/retrieve/pii/S0149-2918(05)00178-5}}</ref> both provide protection by acting as an antihistamine and a mast cell stabilizer together. Patanol is a prescription medication, whereas Ketotifen Fumarate is not.
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| It is mandatory that the patients not use anything besides clean, warm water until visiting their doctors. Many of the eye drops can cause burning and stinging, and usually nearly all medications have [[side-effects]]. Therefore, patients are strongly recommended to first talk to their doctors before using any type of medication.
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| Individuals prone to developing allergenic conjunctivitis may prevent getting the condition by having proper eye [[hygiene]], especially if wearing contact lenses. People allergic to pollen or mold are also advised to stay indoors when allergen levels are high. Allergic persons are recommended to keep the doors and windows closed and use air conditioners during the summer months to prevent developing allergic conjunctivitis.
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| ==Epidemiology==
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| Allergic conjunctivitis occurs more frequently among those with allergic conditions, with the symptoms having a seasonal correlation.<ref name="StateU">{{cite web|url=http://encyclopedia.stateuniversity.com/pages/4940/conjunctivitis.html#ixzz0jIjU1c1G |title=Conjunctivitis - Epidemiology, Diagnosis, Treatment and management |publisher=encyclopedia.stateuniversity.com |accessdate=2010-04-06| archiveurl= http://web.archive.org/web/20100409111603/http://encyclopedia.stateuniversity.com/pages/4940/conjunctivitis.html| archivedate= 9 April 2010 <!--DASHBot-->| deadurl= no}}</ref> | |
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| Allergic conjunctivitis is a frequent condition as it is estimated to affect 20 percent of the [[population]] on an annual basis and approximately one-half of these people have a personal or family history of [[atopy]].<ref name="Bl">{{cite web|url=http://www.conjunctivitis.blogspot.com/ |title=Conjunctivitis: Differentiating Allergic, Bacterial & Viral Conjunctivitis |publisher=conjunctivitis.blogspot.com |accessdate=2010-04-06}}</ref>
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| Giant papillary conjunctivitis accounts for 0.5–1.0% of [[eye disease]] in most countries.
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| ==References==
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| {{Reflist|2}}
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| | == Case Studies == |
| | [[Allergic conjunctivitis case study one|Case #1]] |
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| {{Allergic conditions}} | | {{Allergic conditions}} |
| {{Eye pathology}} | | {{Eye pathology}} |
| {{Hypersensitivity and autoimmune diseases}} | | {{Hypersensitivity and autoimmune diseases}} |
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| [[Category:Primary care]]
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| [[Category:Allergy]]
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| [[Category:ophthalmology]]
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| [[ca:Conjuntivitis al·lèrgica]] | | [[ca:Conjuntivitis al·lèrgica]] |
| [[de:Konjunktivitis#Conjunktivitis_allergica]] | | [[de:Konjunktivitis#Conjunktivitis_allergica]] |
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