Conjunctivitis

Conjunctivitis
An eye with viral conjunctivitis
Classification and external resources
ICD-10	H10
ICD-9	372.0
DiseasesDB	3067
MedlinePlus	001010
eMedicine	emerg/110
Patient UK	Conjunctivitis
MeSH	D003231

Conjunctivitis, also known as pink eye^[1] or Madras eye^[2] is inflammation of the conjunctiva (the outermost layer of the eye and the inner surface of the eyelids).^[1] It is commonly due to an infection (usually viral, but sometimes bacterial^[3]) or an allergic reaction.

Classification

Classification can be either by cause or by extent of the inflamed area.

Causes

• Allergic conjunctivitis, caused by allergens such as pollen, perfumes, cosmetics, smoke,^[4] dust mites, Balsam of Peru (used in food and drink for flavoring, in perfumes and toiletries for fragrance, and in medicine and pharmaceutical items for healing properties),^[5] and eye drops.^[6] A patch test is used to diagnose it and identify the causative allergen.^[7]
• Bacterial conjunctivitis
• Viral conjunctivitis
• Chemical conjunctivitis
• Neonatal conjunctivitis is often defined separately due to different organisms
• Autoimmune

By extent of involvement

Blepharoconjunctivitis is the dual combination of conjunctivitis with blepharitis (inflammation of the eyelids).

Keratoconjunctivitis is the combination of conjunctivitis and keratitis (corneal inflammation).

Signs and symptoms

Red eye (hyperaemia), swelling of conjunctiva (chemosis) and watering (epiphora) of the eyes are symptoms common to all forms of conjunctivitis. However, the pupils should be normally reactive, and the visual acuity normal.

Viral

Viral conjunctivitis is often associated with an infection of the upper respiratory tract, a common cold, and/or a sore throat. Its symptoms include excessive watering and itching. The infection usually begins with one eye, but may spread easily to the other.

Viral conjunctivitis shows a fine, diffuse pinkness of the conjunctiva, which is easily mistaken for the ciliary infection of Iris (Iritis), but there are usually corroborative signs on microscopy, particularly numerous lymphoid follicles on the tarsal conjunctiva, and sometimes a punctate keratitis.

Some other viruses that can infect the eye include Herpes simplex virus and Varicella zoster.^[8]

Allergic

Allergic conjunctivitis is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy.^[9] Allergens differ among patients. Symptoms consist of redness (mainly due to vasodilation of the peripheral small blood vessels), oedema (swelling) of the conjunctiva, itching, and increased lacrimation (production of tears). If this is combined with rhinitis, the condition is termed "allergic rhinoconjunctivitis".

The symptoms are due to release of histamine and other active substances by mast cells, which stimulate dilation of blood vessels, irritate nerve endings, and increase secretion of tears.

Bacterial

Bacterial conjunctivitis causes the rapid onset of conjunctival redness, swelling of the eyelid, and mucopurulent discharge. Typically, symptoms develop first in one eye, but may spread to the other eye within 2–5 days. Bacterial conjunctivitis due to common pyogenic (pus-producing) bacteria causes marked grittiness/irritation and a stringy, opaque, greyish or yellowish mucopurulent discharge that may cause the lids to stick together, especially after sleep. Severe crusting of the infected eye and the surrounding skin may also occur. The gritty and/or scratchy feeling is sometimes localized enough for patients to insist they must have a foreign body in the eye. The more acute pyogenic infections can be painful. Common bacteria responsible for non-acute bacterial conjunctivitis are Staphylococci and Streptococci.^[10]

Bacteria such as Chlamydia trachomatis or Moraxella can cause a non-exudative but persistent conjunctivitis without much redness. Bacterial conjunctivitis may cause the production of membranes or pseudomembranes that cover the conjunctiva. Pseudomembranes consist of a combination of inflammatory cells and exudates, and are loosely adherent to the conjunctiva, while true membranes are more tightly adherent and cannot be easily peeled away. Cases of bacterial conjunctivitis that involve the production of membranes or pseudomembranes are associated with Neisseria gonorrhoeae, β-hemolytic streptococci, and C. diphtheriae. Corynebacterium diphtheriae causes membrane formation in conjunctiva of non-immunized children.

Chemical

Chemical eye injury is due to either an acidic or alkali substance getting in the eye.^[11] Alkalis are typically worse than acidic burns.^[12] Mild burns will produce conjunctivitis, while more severe burns may cause the cornea to turn white.^[12] Litmus paper is an easy way to rule out the diagnosis by verifying that the pH is within the normal range of 7.0—7.2.^[11] Large volumes of irrigation is the treatment of choice and should continue until the pH is 6—8.^[12] Local anaesthetic eye drops can be used to decrease the pain.^[12]

Irritant or toxic conjunctivitis show primarily marked redness. If due to splash injury, it is often present in only the lower conjunctival sac. With some chemicals, above all with caustic alkalis such as sodium hydroxide, there may be necrosis of the conjunctiva with a deceptively white eye due to vascular closure, followed by sloughing of the dead epithelium. This is likely to be associated with slit-lamp evidence of anterior uveitis.

Other

Inclusion conjunctivitis of the newborn (ICN) is a conjunctivitis that may be caused by the bacteria Chlamydia trachomatis, and may lead to acute, purulent conjunctivitis.^[13] However, it is usually self-healing.^[13]

Conjunctivitis is identified by irritation and redness of the conjunctiva. Except in obvious pyogenic or toxic/chemical conjunctivitis, a slit lamp (biomicroscope) is needed to have any confidence in the diagnosis. Examination of the tarsal conjunctiva is usually more diagnostic than the bulbar conjunctiva.

Causes

Conjunctivitis when caused by an infection is most commonly caused by a viral infection.^[14] Bacterial infections, allergies, other irritants and dryness are also common causes. Both bacterial and viral infections are contagious and passed from person to person, but can also spread through contaminated objects or water.

The most common cause of viral conjunctivitis is adenoviruses (see: Adenoviral keratoconjunctivitis).^[15] Herpetic keratoconjunctivitis (caused by herpes simplex viruses) can be serious and requires treatment with acyclovir. Acute hemorrhagic conjunctivitis is a highly contagious disease caused by one of two enteroviruses, Enterovirus 70 and Coxsackievirus A24. These were first identified in an outbreak in Ghana in 1969, and have spread worldwide since then, causing several epidemics.^[16]

The most common causes of acute bacterial conjunctivitis are Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae.^[15] Though very rare, hyperacute cases are usually caused by Neisseria gonorrhoeae or N. meningitidis. Chronic cases of bacterial conjunctivitis are those lasting longer than 3 weeks, and are typically caused by Staphylococcus aureus, Moraxella lacunata, or gram-negative enteric flora.

Conjunctivitis may also be caused by allergens such as pollen, perfumes, cosmetics, smoke,^[4] dust mites, Balsam of Peru,^[5] and eye drops.^[6]

An exceptional case of conjunctivitis induced by a trombiculid mite (Neotrombicula autumnalis) was reported in 2013.^[17]

Conjunctivitis is part of the triad of reactive arthritis, which is thought to be caused by autoimmune cross-reactivity following certain bacterial infections. Reactive arthritis is highly associated with HLA-B27. Conjunctivitis is associated with the autoimmune disease relapsing polychondritis.^[18][19]

Diagnosis

Cultures are not often taken or needed as most cases resolve either with time or typical antibiotics. Swabs for bacterial culture are necessary if the history and signs suggest bacterial conjunctivitis but there is no response to topical antibiotics. Viral culture may be appropriate in epidemic case clusters.

A patch test is used to identify the causative allergen in the case where conjunctivitis is caused by allergy.^[7]

Conjunctival scrapes for cytology can be useful in detecting chlamydial and fungal infections, allergy, and dysplasia, but are rarely done because of the cost and the general lack of laboratory staff experienced in handling ocular specimens. Conjunctival incisional biopsy is occasionally done when granulomatous diseases (e.g., sarcoidosis) or dysplasia are suspected.

Differential diagnosis

Conjunctivitis causes relatively nonspecific symptoms.^[1] Even after biomicroscopy, laboratory tests are often necessary if proof of etiology is needed.

A purulent discharge (a whitish-yellow, yellow or yellow-brown substance, more commonly known as pus) suggests a bacterial infection. It can also be caused by bacteria from feces, pet hair, or by smoke or other fumes. Infection with Neisseria gonorrhoeae should be suspected if the discharge is particularly thick and copious.

Itching (rubbing eyes) is the hallmark symptom of allergic conjunctivitis. Other symptoms include history of eczema, or asthma.

A diffuse, less "injected" conjunctivitis (looking pink rather than red) suggests a viral cause, especially if numerous follicles are present on the lower tarsal conjunctiva on biomicroscopy.

Scarring of the tarsal conjunctiva suggests trachoma, especially if seen in endemic areas, if the scarring is linear (Arlt's line), or if there is also corneal vascularization.

Clinical tests for lagophthalmos, dry eye (Schirmer test) and unstable tear film may help distinguish the various types of conjunctivitis.

Other symptoms, including pain, blurring of vision and photophobia, should not be prominent in conjunctivitis. Fluctuating blurring is common, due to tearing and mucoid discharge. Mild photophobia is common. However, if any of these symptoms are prominent, it is important to consider other diseases such as glaucoma, uveitis, keratitis and even meningitis or carotico-cavernous fistula.

Many people with conjunctivitis have trouble opening their eyes in the morning because of the dried mucus on their eyelids. There is often excess mucus over the eye after sleeping for an extended period.

Episcleritis is an inflammatory condition that produces a similar appearance to conjunctivitis, but without discharge or tearing.

Prevention

The best effective prevention is hygiene and not rubbing the eyes by infected hands. Vaccination against adenovirus, haemophilus influenzae, pneumococcus, and neisseria meningitidis is also effective.

Management

Conjunctivitis resolves in 65% of cases without treatment, within two to five days. The prescription of antibiotics is not necessary in most cases.^[20]

Viral

Viral conjunctivitis usually resolves on its own and does not require any specific treatment.^[14] Antihistamines (e.g., promethazine) or mast cell stabilizers (e.g., cromolyn) may be used to help with the symptoms.^[14] Povidone iodine has been suggested as a treatment, but as of 2008 evidence to support it was poor.^[21]

Allergic

For the allergic type, cool water poured over the face with the head inclined downward constricts capillaries, and artificial tears sometimes relieve discomfort in mild cases. In more severe cases, nonsteroidal anti-inflammatory medications and antihistamines may be prescribed. Persistent allergic conjunctivitis may also require topical steroid drops.

Bacterial

Bacterial conjunctivitis usually resolves without treatment.^[14] Topical antibiotics may be needed only if no improvement is observed after three days.^[22] In people who received no antibiotics, recovery was in 4.8 days, with immediate antibiotics it was 3.3 days, and with delayed antibiotics 3.9 days. No serious effects were noted either with or without treatment.^[23] As they do speed healing in bacterial conjunctivitis, their use is also reasonable.^[24]

In those who wear contact lenses, are immunocompromised, have disease which is thought to be due to chlamydia or gonorrhea, have a fair bit of pain, or who have lots of discharge, antibiotics are recommended.^[14] Gonorrhea or chlamydia infections require both oral and topical antibiotics.^[14]

When appropriate, the choice of antibiotic varies, differing based on the cause (if known) or the likely cause of the conjunctivitis. Fluoroquinolones, sodium sulfacetamide, or trimethoprim/polymyxin may be used, typically for 7–10 days.^[15] Cases of meningococcal conjunctivitis can be treated with systemic penicillin, as long as the strain is sensitive to penicillin.

Chemical

Conjunctivitis due to chemicals is treated via irrigation with Ringer's lactate or saline solution. Chemical injuries (particularly alkali burns) are medical emergencies, as they can lead to severe scarring and intraocular damage. People with chemically induced conjunctivitis should not touch their eyes, regardless of whether or not their hands are clean, as they run the risk of spreading the condition to another eye.

History

A former superintendent of the Regional Institute of Ophthalmology in the city of Madras (the present-day Chennai) in India, Kirk Patrick, was the first to have found the adenovirus that caused conjunctivitis, leading to the name Madras eye for the disease.^[25]

See also

• Conjunctival suffusion
• Episcleritis

References

External links

Wikimedia Commons has media related to Conjunctivitis.

• Conjunctivitis at DMOZ

Eye disease : Pathology of the eye (H00–H59 360–379)   Adnexa Eyelid Inflammation Stye Chalazion Blepharitis Entropion Ectropion Lagophthalmos Blepharochalasis Ptosis Blepharophimosis Xanthelasma Eyelash Trichiasis Madarosis Lacrimal apparatus Dacryoadenitis Epiphora Dacryocystitis Xerophthalmia Orbit Exophthalmos Enophthalmos Orbital cellulitis Orbital lymphoma Periorbital cellulitis Conjunctiva Conjunctivitis allergic Pterygium Pinguecula Subconjunctival hemorrhage   Globe Fibrous tunic Sclera Scleritis Episcleritis Cornea Keratitis herpetic acanthamoebic fungal Corneal ulcer Photokeratitis Thygeson's superficial punctate keratopathy Corneal dystrophy Fuchs' Meesmann Corneal ectasia Keratoconus Pellucid marginal degeneration (PMD) Keratoglobus Terrien's marginal degeneration Keratoconjunctivitis sicca Corneal neovascularization Kayser–Fleischer ring Haab's striae Arcus senilis Band keratopathy Vascular tunic Iris Ciliary body Uveitis Intermediate uveitis Hyphema Rubeosis iridis Persistent pupillary membrane Iridodialysis Synechia Choroid Choroideremia Choroiditis Chorioretinitis Lens Cataract Congenital cataract Childhood cataract Aphakia Ectopia lentis Retina Retinitis Chorioretinitis Cytomegalovirus retinitis Retinal detachment Retinoschisis Ocular ischemic syndrome / Central retinal vein occlusion Central retinal artery occlusion Retinopathy diabetic hypertensive Purtscher's of prematurity Bietti's crystalline dystrophy Coats' disease Macular degeneration Retinitis pigmentosa Retinal haemorrhage Central serous retinopathy Macular edema Epiretinal membrane (Macular pucker) Vitelliform macular dystrophy Leber's congenital amaurosis Birdshot chorioretinopathy Other Glaucoma / Ocular hypertension / Primary juvenile glaucoma Floater Leber's hereditary optic neuropathy Red eye Keratomycosis Phthisis bulbi Persistent fetal vasculature / Persistent hyperplastic primary vitreous Persistent tunica vasculosa lentis Familial exudative vitreoretinopathy   Pathways Optic nerve Optic disc Optic neuritis optic papillitis Papilledema Foster Kennedy syndrome Optic atrophy Optic disc drusen Optic neuropathy Ischemic anterior (AION) posterior (PION) Kjer's Leber's hereditary Toxic and nutritional Strabismus Extraocular muscles Binocular vision Accommodation Paralytic strabismus Ophthalmoparesis Chronic progressive external ophthalmoplegia Kearns–Sayre syndrome palsies Oculomotor (III) Fourth-nerve (IV) Sixth-nerve (VI) Other strabismus Esotropia / Exotropia Hypertropia Heterophoria Esophoria Exophoria Cyclotropia Brown's syndrome Duane syndrome Other binocular Conjugate gaze palsy Convergence insufficiency Internuclear ophthalmoplegia One and a half syndrome Refraction Refractive error Hyperopia Myopia Astigmatism Anisometropia / Aniseikonia Presbyopia Vision disorders Blindness Amblyopia Leber's congenital amaurosis Diplopia Scotoma Color blindness Achromatopsia Dichromacy Monochromacy Nyctalopia Oguchi disease Blindness / Vision loss / Visual impairment Anopsia Hemianopsia binasal bitemporal homonymous Quadrantanopia subjective Asthenopia Hemeralopia Photophobia Scintillating scotoma Pupil Anisocoria Argyll Robertson pupil Marcus Gunn pupil Adie syndrome Miosis Mydriasis Cycloplegia Parinaud's syndrome Other Nystagmus Childhood blindness   Infections Trachoma Onchocerciasis Index of the eye Description Anatomy orbit neural pathways Physiology Phenomena appearance visual optical illusions proteins Development Disease Congenital Corneal dystrophy Neoplasms and cancer Other Symptoms and signs Treatment Procedures Drugs infection glaucoma and miosis mydriatics vascular

Inflammation Acute Plasma derived mediators Bradykinin complement C3 C5a MAC coagulation Factor XII Plasmin Thrombin Cell derived mediators preformed: Lysosome granules biogenic amines Histamine Serotonin synthesized on demand: cytokines IFN-γ IL-8 TNF-α IL-1 eicosanoids Leukotriene B4 Prostaglandins Nitric oxide Kinins Chronic Macrophage Epithelioid cell Giant cell Granuloma Processes Traditional: Rubor Calor Tumor Dolor (pain) Functio laesa Modern: Acute-phase reaction/Fever Vasodilation Increased vascular permeability Exudate Leukocyte extravasation Chemotaxis Specific locations Nervous CNS Encephalitis Myelitis Meningitis Arachnoiditis PNS Neuritis eye Dacryoadenitis Scleritis Episcleritis Keratitis chorioretinitis Retinitis Chorioretinitis Blepharitis Conjunctivitis Uveitis ear Otitis Labyrinthitis Mastoiditis Cardiovascular Carditis Endocarditis Myocarditis Pericarditis Vasculitis Arteritis Phlebitis Capillaritis Respiratory upper Sinusitis Rhinitis Pharyngitis Laryngitis lower Tracheitis Bronchitis Bronchiolitis Pneumonitis Pleuritis Mediastinitis Digestive mouth Stomatitis Gingivitis Gingivostomatitis Glossitis Tonsillitis Sialadenitis/Parotitis Cheilitis Pulpitis Gnathitis tract Esophagitis Gastritis Gastroenteritis Enteritis Colitis Enterocolitis Duodenitis Ileitis Caecitis Appendicitis Proctitis accessory Hepatitis Ascending cholangitis Cholecystitis Pancreatitis Peritonitis Integumentary Dermatitis Folliculitis Cellulitis Hidradenitis Musculoskeletal Arthritis Dermatomyositis soft tissue Myositis Synovitis/Tenosynovitis Bursitis Enthesitis Fasciitis Capsulitis Epicondylitis Tendinitis Panniculitis Osteochondritis: Osteitis/Osteomyelitis Spondylitis Periostitis Chondritis Urinary Nephritis Glomerulonephritis Pyelonephritis Ureteritis Cystitis Urethritis Reproductive female: Oophoritis Salpingitis Endometritis Parametritis Cervicitis Vaginitis Vulvitis Mastitis male: Orchitis Epididymitis Prostatitis Seminal vesiculitis Balanitis Posthitis Balanoposthitis pregnancy/newborn: Chorioamnionitis Funisitis Omphalitis Endocrine Insulitis Hypophysitis Thyroiditis Parathyroiditis Adrenalitis Lymphatic Lymphangitis Lymphadenitis