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Conjunctivitis is an inflammation of the conjunctiva due to infectious agents or allergens that may irritate the covering layer.


Patients present with follicles on the eyelids and a thin, watery purulent discharge from both eyes. There is ocular pain, redness (hence the name pink eye) and eyelid and periorbital edema. Patients often complain of difficulty in opening the eyes in the mornings and pain upon straining the eyes. A study conducted about presenting symptoms of conjunctivitis in 2013 revealed that ocular complains such as itching, tearing, photophobia and discomfort of the eyes lead most of the patients to be diagnosed of allergic conjunctivitis [7].

Pleural Effusion
  • Systemic signs of tuberculosis were noted in two patients--pleural effusion in one and preauricular and submandibular lymph node involvement in the other.[ncbi.nlm.nih.gov]
Heart Disease
  • […] hay fever Bites, burns, cuts and pests Blood, organ and tissue Cancer Challenging behaviour Chemicals and contaminants Diabetes Dementia Dental care Drugs End of life care Essure contraceptive device Falls and preventing harm from falls Food safety Heart[sahealth.sa.gov.au]
Red Eye
  • We report the case of a 79-year-old woman with a long history of red eye and relapsing conjunctivitis-blepharitis caused by ocular rosacea.[ncbi.nlm.nih.gov]
  • The differential diagnosis for red eye is broad because many ophthalmic conditions masquerade as conjunctivitis (Table). View this table: In this window In a new window Table.[dx.doi.org]
  • Author information 1 Department of Ophthalmology, Inverclyde Royal Hospital, Glasgow PA16 0XN, UK. tzvandasara@nhs.net Abstract It is not uncommon for patients to present to eye casualties with a red eye and where treatment has already been started by[ncbi.nlm.nih.gov]
  • In severe adenoviral conjunctivitis, patients may have photophobia and foreign body sensation due to corneal involvement. Chemosis may be present.[msdmanuals.com]
  • Pain, loss of vision or photophobia require immediate referral to an ophthalmologist .[dermnetnz.org]
  • Occasionally, severe photophobia and foreign-body sensation occurs, usually caused by adenovirus (epidemic keratoconjunctivitis [EKC]), when associated with keratitis.[emedicine.com]
Eye Pain
  • All patients with a history of contact lens wear and red flag symptoms such as eye pain, redness, reduction or change in vision, corneal epithelial defect, discharge, foreign body sensation or failure to respond to antibiotics should be referred for an[ncbi.nlm.nih.gov]
  • Eye pain is minimal or absent with allergic conjunctivitis. Frequent causes include seasonal pollens, animal dander, and dust.[medicinenet.com]
  • Pinkeye (Conjunctivitis) Symptom Eye Pain Eye pain is often described as burning, sharp, shooting, dull, gritty, a feeling of "something in my eye," aching, pressure, throbbing, or stabbing.[emedicinehealth.com]
  • These conditions may cause eye pain, a feeling that something is stuck in your eye (foreign body sensation), blurred vision and light sensitivity. If you experience these symptoms, seek urgent care.[mayoclinic.org]
  • We report the case of a 79-year-old woman with a long history of red eye and relapsing conjunctivitis-blepharitis caused by ocular rosacea.[ncbi.nlm.nih.gov]
  • This type of conjunctivitis is often associated with blepharitis. Symptoms can include redness of the conjunctiva, burning, frequent styes, foreign body sensation and morning eyelash crusting or eyelash loss.[hopkinsmedicine.org]
  • Chronic and severe anterior blepharitis : the reduction in the tear film associated with blepharitis can cause chronic irritation and scarring. Drugs : may cause mild-to-severe irritation.[patient.info]
  • Häufige Begriffe und Wortgruppen abnormalities Acad Dermatol acute antibodies antigen Arch Dermatol Arch Ophthalmol areas arthritis associated biopsy blepharitis cause cell carcinoma choroidal chronic cicatricial pemphigoid Clin CLINICAL FEATURES Dermatologic[books.google.com]
Excessive Tearing
  • Aside from its trademark pink coloration, other telltale signs of pink eye include: Feeling of foreign objects in one or both eyes Itching or burning in one or both eyes Yellowish discharge from one or both eyes Excess tearing from one or both eyes Build-up[bausch.com]
  • Conjunctivitis symptoms Conjunctivitis leads to: Eye irritation and redness Excessive tears in the eyes A discharge with pus Swelling of the eyelids Photophobia (you can’t tolerate looking into sunlight).[betterhealth.vic.gov.au]
  • Allergic Itching, redness, and excessive tearing, usually of both eyes. Chemical Red, watery eyes, especially after swimming in chlorinated water. Immune mediated, such as that related to a systemic disease like Kawasaki disease.[healthychildren.org]


Laboratory tests

  • Complete blood count
  • Conjunctival scrapings and culture
  • Eversion of eyelid at slit lamp
  • Blood culture
  • Tests for STDs if genital symptoms are also present


Imaging studies are not required to diagnose conjunctivitis. Orbital CT scan, MRI and a colour Doppler exam may be done to rule out other diseases.

Test results

Conjunctivitis is easily diagnosed with the help of a clinical examination. Laboratory tests may be done to confirm the diagnosis and identify the causative organism.

Pleural Effusion
  • Systemic signs of tuberculosis were noted in two patients--pleural effusion in one and preauricular and submandibular lymph node involvement in the other.[ncbi.nlm.nih.gov]


Benign cases of conjunctivitis usually do not require pharmacologic treatment as they tend to resolve on their own. Almost all the patients that suffer from bacterial conjunctivitis have a self-limiting condition and no treatment is required in uncomplicated cases. That said, it should be noted that conjunctivitis which is caused by such organisms that typically cause venereal diseases like chlamydia, and conjunctivitis occurring in optic lens wearers should be treated with appropriate antibiotics [8]. Medication is not required for viral conjunctivitis as the condition is mild, of short duration and seldom has any lasting effects.

The drugs that may be used include non steroidal anti-inflammatory drugs and glucocorticoids. Glucocorticoids suppress the late-phase reaction of allergic inflammation and are effective in treating bacterial conjunctivitis [9]. Antihistamines are only used for chronic conjunctivitis only because full efficacy is reached after 5 to 14 days after therapy and therefore these medicines are not useful for relieving acute symptoms of conjunctivitis [10]


Conjunctivitis has an excellent prognosis and often resolves spontaneously when the infection has run its course. It is also completely and effectively treated with the help of antibiotics and anti-inflammatory drugs.


Conjunctivitis is due to a bacterial, viral or fungal infection. Viral conjunctivitis is the most common overall cause of infectious conjunctivitis and usually does not require treatment; the signs and symptoms at presentation are variable. Bacterial infections are the second most common cause of conjunctivitis. Strains of the common human pathogen Streptococci pneumoniae lacking the capsule are the main virulence factor. This is the target of current vaccines [2]. Other bacteria that can cause conjunctivitis include Chlamydia trachomatis, Neisseria gonorrhoeae. A cross sectional descriptive study conducted on patients with acute conjunctivitis found that Chlamydia trachomatis accounts for one third of the cases of acute conjunctivitis [3].

Non-infectious causes of conjunctivitis include allergic agents like pollen grains and other particulate matter that enter and settle in the inner surface of the eyelids adjacent to the conjunctiva. This will cause local irritation and itching and inflammation, that manifest as conjunctivitis.



Ocular allergy is estimated to affect at least 20 percent of the population on an annual basis, and the incidence is increasing [4]. According to a study, 4.4% out of a total of 1079 observed patients with ocular allergy had acute conjunctivitis [5].


Conjunctivitis is known to occur equally in both sexes.


Conjunctivitis does not have a predisposition to any particular age group, however the age of patients of conjunctivitis is relevant in identifying the causative agent. For example, a young, sexually active person is more likely to be suffering from conjunctivitis from a sexually transmitted disease (STD).

Sex distribution
Age distribution


The factors responsible the conjunctivitis and iritis associated with acute ocular infection and post enteric inflammatory disease are not fully known [6]. It is known however that the inflammatory markers and mediators such as leukotrienes, interleukins and cytokines play an important role in the development of conjunctivitis. When any irritant, be it in the form of virus, bacteria or a particulate matter enters and settles inside the eyelid, adjacent to the conjunctiva, it causes irritation of the conjunctiva. If the irritant remains there for sufficient time, and the person is unable to dislodge it with tearing and/or rubbing, inflammation begins.

Another pathway is the internal pathway where the causative agents, usually microbes such as the ones causing STDs, enter into the orbital blood supply and start to multiply in the orbital cavity, resulting in inflammation. Or the person may already be suffering from an infection such as an upper respiratory tract infection and the infectious agents may infect the eye as well, either due to direct contact such as rubbing the eyes with unclean fingers or through circulating antigens in the blood.
Whatever the initial route or pathway maybe, the end result is same: inflammation. Although the outer epithelial layer provides some defence, it is easily torn or broken and conjunctivitis develops.


Conjunctivitis may be prevented by maintaining good hygiene of the eyes. Regular testing for STDs in sexually active people is recommended and the patients suffering from upper respiratory tract infections or other easily transmissible infections should take appropriate treatment to eradicate the disease from their body.


Conjunctivitis is an inflammation of the conjunctiva, which is an outer transparent covering of the eyeball. It is also known as the ‘Pink Eye’ in many regions of North America [1]. It is a common condition and is seldom reported due to its mild nature. However, not all cases are benign and some may leave serious damage and lasting ill effects if not treated adequately with appropriate antibiotics.

Patient Information


Conjunctivitis is a condition in which inflammation of the conjunctiva, which is a membrane coating the eyeball and the inner surface of the eyelids, takes place.


It is most often due to a viral or bacterial infection but sometimes, the entry of tiny particulate matter, eyelashes, dust, pollen grains, etc can also cause conjunctivitis.

Signs and symptoms

Signs and symptoms include redness of the eye with watery, purulent discharge. There may be slight puffiness and swelling of the eye, pain on straining or exposure to bright lights, itching and burning. 


Diagnosis is made clinically and is supported with laboratory tests.


Treatment is mainly supportive, particularly in cases of viral conjunctivitis. If the condition is due to a foreign particle in the eye, it should be removed so that the eye can heal. If there is a bacterial infection, antibiotics and anti-inflammatory drugs may be used.



  1. Richards A, Guzman-Cottrill JA. Conjunctivitis. Pediatr Rev, May 2010. 31 (5): 196–208.
  2. Valentino MD, McGuire AM, Rosch JW, Bispo PJ, Burnham C, Sanfilippo CM, Carter RA, Zegans ME, Beall B, Earl AM, Tuomanen EI, Morris TW, Haas W, Gilmore MS. Unencapsulated Streptococcus pneumoniae from conjunctivitis encode variant traits and belong to a distinct phylogenetic cluster. Nat Commun. 2014 Nov 12;5:5411. 
  3. Mowafy MA, Saad NE, El-Mofty HM, ElAnany MG, Mohamed MS. The prevalence of chlamydia trachomatis among patients with acute conjunctivitis in Kasr Alainy ophthalmology clinic. Pan Afr Med J. 2014 Mar 3;17:151. 
  4. Wang HY, Pizzichini MM, Becker AB, et al. Disparate geographic prevalences of asthma, allergic rhinoconjunctivitis and atopic eczema among adolescents in five Canadian cities. Pediatr Allergy Immunol 2010; 21:867.
  5. Uchio E, Kimura R, Migita H, et al. Demographic aspects of allergic ocular diseases and evaluation of new criteria for clinical assessment of ocular allergy. Graefes Arch Clin Exp Ophthalmol 2008; 246:291.
  6. Langford MP, Foreman BD, Srur L, Ganley JP, Redens TB. Bilateral acute pyogenic conjunctivitis with iritis induced by unilateral topical application of bacterial peptidoglycan muramyl dipeptide in adult rabbits. Exp Eye Res. 2013 Nov;116:324-36.
  7. Chiambaretta F, Gerbaud L, Fauquert JL. Management of allergic conjunctivitis. An observational study among ophthalmologists. [Article in French]. J Fr Ophtalmol. 2014 Jan;37(1):9-17. 
  8. Azari AA, Barney NP. Conjunctivitis: a systematic review of diagnosis and treatment. JAMA. 2013 Oct 23;310(16):1721-9. 
  9. Schleimer RP. Effects of glucocorticosteroids on inflammatory cells relevant to their therapeutic applications in asthma. Am Rev Respir Dis 1990; 141:S59.
  10. Nizami RM. Treatment of ragweed allergic conjunctivitis with 2% cromolyn solution in unit doses. Ann Allergy 1981; 47:5.

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Last updated: 2018-06-22 10:22