History and exam

Key diagnostic factors

common

watery discharge

Common in allergic conjunctivitis.[1]​​

ropy, mucoid discharge

More common in allergic than viral or bacterial infection.[7][8][16][17][18][40]

purulent discharge

More common in bacterial than viral infection.[16][17][18][40] Copious purulent discharge developing over 12 to 24 hours can indicate a hyperacute gonococcal infection.

itching predominant symptom

More common in allergic than viral infection, particularly in seasonal allergic conjunctivitis.[7][8]

red eye

Most forms of conjunctivitis can present with conjunctival injection (vasodilation with hyperemia).[1]​​

eyelids stuck together in morning

Occurs with both bacterial and viral infection.[16][17][18][40]

tender, preauricular lymphadenopathy

More common in viral than bacterial infection.[16][17][18][40] May also occur in gonococcal and chlamydial conjunctivitis.[1]​​

Other diagnostic factors

common

conjunctival follicles

Present in viral infection.[16][17][18][40] May also occur in medication-induced conjunctivitis.[1]​​

chemosis

Chemosis, swelling of the conjunctiva, can be present in allergic, adenoviral, and chlamydial conjunctivitis.[1]​​[7]

swollen eyelids

Eyelid edema may be present in allergic, mechanical, medication-induced, gonococcal, and chlamydial conjunctivitis.[1]​​[7]

superficial punctate keratopathy

Present in viral and mechanical conjunctivitis.[1]​​[16][17][18][40]

unilateral symptoms and signs

More common in bacterial than viral infection.[16][17][18][40] All forms of allergic conjunctivitis are bilateral.[1]​

use of medications that may lead to eye irritation

Certain topical and systemic medications, such as topical glaucoma medications, antibiotics, and antivirals, and oral antihistamine/anticholinergic drugs may irritate the eye and lead to conjunctivitis.[1]​​

contact lens use

Giant papillary conjunctivitis can be caused by chronic mechanical interaction of contact lenses. Soft contact lens wearers have a high risk of bacterial keratitis, especially with use of extended-wear lenses. In addition, infrequent replacements of lenses, wearing lenses for a long time, poor hygiene with lenses, lens solutions that are allergenic, high water content of lenses, and poor fit of lenses make giant papillary conjunctivitis more likely.[1]​​

uncommon

corneal subepithelial infiltrates

May be present in viral and bacterial infection.

corneal pannus

May be present in viral and bacterial infection.

vesicular skin rash

May indicate herpes (simplex or varicella zoster) infection.[1]​​

symptoms and signs of related systemic disease

Symptoms and signs of rhinitis or asthma, or both, may be present in allergic conjunctivitis.[7] Genitourinary discharge and dysuria may be present in chlamydial or gonococcal conjunctivitis. Upper respiratory infection symptoms may be present in infectious conjunctivitis. Bacterial conjunctivitis may be associated with concurrent bacterial otitis media, sinusitis, or pharyngitis. Atopic dermatitis may be present in atopic conjunctivitis. There may also be a history of chickenpox (varicella zoster virus), or carcinoma, or leukemia, or graft versus host disease, or Stevens-Johnson syndrome/toxic epidermal necrolysis (TEN), all of which are associated with conjunctivitis. An immunocompromised state may lead to ocular infection with molluscum contagiosum. Floppy eyelid syndrome, which is associated with obesity and sleep apnea, may lead to chronic upper lid inversion and mechanical trauma when sleeping. There may also be a history of concomitant ocular surface disease.[1]​​

Risk factors

strong

exposure to infected person

Infectious conjunctivitis is very contagious.[1]​​

infection in one eye

Conjunctivitis can spread from one eye to the other, especially with viral conjunctivitis.

environmental irritants

Includes outdoor air pollution, dust storms, traffic pollution, and tobacco smoke.[1]​​[38]

allergen exposure

Cause of allergic conjunctivitis. Includes grasses, trees, pollens, ragweed, cats, dogs.[1]​​[7][39]

concurrent infection

An upper respiratory infection may be present in infectious conjunctivitis. Bacterial conjunctivitis may be associated with concurrent bacterial otitis media, sinusitis, or pharyngitis.[1]​​

camps, swimming pools, military bases

Often transmitted between people in close contact. Viral spread is more prevalent than bacterial spread in these situations.[16][17][18][40]

hot, dry climate

Vernal keratoconjunctivitis prevalence varies widely geographically and has seasonal variation, greatest in hot, dry climates, highest incidence in African countries.[12]

Characteristically affects young males.[41][42]

atopic dermatitis

Around 25% of people with atopic dermatitis have ocular involvement.[7][8]

contact lens use

Giant papillary conjunctivitis can be caused by chronic mechanical interaction of contact lenses.[1]​ Soft contact lens wearers have a high risk of bacterial keratitis, especially with use of extended-wear lenses. In addition, infrequent replacements of lenses, wearing lenses for a long time, poor hygiene with lenses, lens solutions that are allergenic, high water content of lenses, and poor fit of lenses make giant papillary conjunctivitis more likely.​[1]

ocular prosthesis

Giant papillary conjunctivitis can be caused by chronic mechanical interaction of prosthesis.[1]

trauma: mechanical, chemical, or ultraviolet

Floppy eyelid syndrome, which is associated with obesity and sleep apnea, may lead to chronic upper lid inversion and mechanical trauma when sleeping.

Mechanical trauma can cause factitious conjunctivitis and mucus fishing syndrome.[43]

Toxic/chemical conjunctivitis results from irritation of the conjunctiva by environmental exposure to chemicals (including acids and bases). Ultraviolet light may predispose to ocular surface squamous neoplasia and melanoma, and may also reactivate herpes simplex virus.[1]​​

recent surgery or exposed sutures

Recent surgery or exposed sutures can make conjunctivitis more likely.​[1]

rosacea

Rosacea may have ocular manifestations, including red eye and irritation.​[1]

allogeneic stem cell transplantation

Patients who have had allogeneic stem cell transplantation may have conjunctivitis associated with graft versus host disease.[1]

Stevens-Johnson syndrome/toxic epidermal necrolysis (TEN)

Patients with Stevens-Johnson syndrome/toxic epidermal necrolysis (TEN) may experience conjunctivitis if triggered by a particular medication or infectious agent.​[1]

prior infection with herpes simplex virus

Reactivation of herpes simplex virus may lead to conjunctivitis.[1]

in neonate: vaginal delivery

In a neonate, vaginal delivery by an infected mother may predispose to conjunctivitis.​[1]

oculogenital spread

Certain infectious agents may be spread via the oculogenital route; in children, this may be a sign of sexual abuse.[1]

weak

asthma

Allergic conjunctivitis is more prevalent in people with asthma.

hay fever

Allergic conjunctivitis is more prevalent in people with hay fever.

use of topical eye medications

Some eye preparations (such as glaucoma medications, antibiotics, and antivirals) contain the preservative, benzalkonium chloride, that can accumulate in the conjunctiva after frequent administration, potentially resulting in toxic keratoconjunctivitis.[28]​

use of oral antihistamine or anticholinergic drugs

Oral medications with antihistamine or anticholinergic adverse effects can lead to dry eyes, which may reduce the protective mechanism of the eye and predispose to conjunctivitis.[31]

neoplasia

Sebaceous gland carcinoma may be a cause of chronic conjunctivitis. Radiation therapy for this type of cancer may induce pathologic changes in the conjunctiva, including loss of goblet cells and accessory lacrimal glands, causing dryness and irritation. Ocular surface squamous neoplasia, conjunctival lymphoma, and melanoma may also be associated with conjunctivitis.[1]​​

history of rheumatologic disease

More common with allergic conjunctivitis than viral and bacterial forms.[44]

dysthyroid states

Certain types of conjunctivitis are associated with dysthyroid states: for example, superior limbic keratoconjunctivitis.[1]​​

immunocompromised state

An immunocompromised state may lead to ocular infection with molluscum contagiosum.[1]​​

vasculitis

Certain types of vasculitis can lead to conjunctivitis.[1]​​

nasolacrimal duct obstruction

In an infant, nasolacrimal duct obstruction may predispose to conjunctivitis.[1]​​

abnormality of supporting structures of the eye (adnexa)

Abnormalities of the adnexal structure may predispose to bacterial infection.[1]​​

severe tear deficiency

Severe tear deficiency may predispose to bacterial infection.[1]​​

trauma

Trauma may predispose to bacterial infection.

use of biologic agents

Reported ocular adverse effects of dupilumab, a monoclonal antibody used for the treatment of moderate to severe atopic dermatitis and asthma, include conjunctivitis, dry eyes, and blepharitis.[1][34][35]

Tralokinumab for the treatment of atopic dermatitis has been associated with conjunctivitis.[45]

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