Is Conjunctivitis Contagious?

Brief overview

What is conjunctivitis? An infectious or non-infectious inflammation of the conjunctiva. The medical term is conjunctivitis.
Causes: Infectious agents (such as bacteria, viruses), allergies, foreign bodies in the eye (e.g. dust), damaged contact lenses, UV light, drafts, eyestrain, and more.
common symptoms: reddened, watery and (especially in the morning) sticky eye, swollen eyelid, swollen conjunctiva, burning and/or itching in the eye, foreign body sensation in the eye
Treatment: depending on the cause, e.g. antibiotics in case of bacterial conjunctivitis (mostly as eye drops); in case of allergic conjunctivitis anti-allergic eye drops, if necessary eye drops containing cortisone; in general: eliminate or avoid triggers if possible.
Is conjunctivitis contagious? Bacterial and viral conjunctivitis are highly contagious! As an infected person, do not touch your eyes, ensure careful hand hygiene and use your own towel.

Typical for conjunctivitis are symptoms like:

red, watery eye

increased discharge (secretion) from the eye and thus often blurred vision and especially in the morning sticky eye

swollen eyelid, swollen conjunctiva (conjunctiva looks glassy swollen)

photophobia/sensitivity to glare

Foreign body sensation or feeling of pressure in the eye
@ Burning and/or itching in the eye

There may be specifics regarding symptoms depending on the trigger of conjunctivitis. Examples:

Form of conjunctivitis	specific symptoms
Bacterial conjunctivitis	– Eye secretion is thick white, green or yellow (purulent) – usually starts in one eye and then spreads to the second within a few days
Viral conjunctivitis	– Eye secretion rather watery (serous) – Lymph nodes in front of the ear sometimes swollen and painful – Irritation of the affected eye – usually starts in one eye and then quickly spreads to the second eye
Allergic conjunctivitis	– in the foreground are violent eye itching or burning as well as watery or thread-drawing discharge – both eyes affected – seasonal allergic conjunctivitis: additional allergy symptoms such as itchy, runny nose – keratoconjunctivitis vernalis: additionally corneal inflammation, partly with painful, open corneal ulcers
Other forms of conjunctivitis	– Conjunctivitis due to foreign bodies such as dust or smoke in the eye: disturbing, rubbing sensation in the eye – Conjunctivitis due to excessive exposure to light: in addition to sensitivity to light, also pain in the eye and headache

Conjunctivitis: Treatment

As with other illnesses of the eye also, one should go also with a conjunctivitis in each case to the ophthalmologist! Depending on the cause of conjunctivitis, he can initiate appropriate treatment and thus prevent permanent eye damage if necessary.

Bacterial conjunctivitis: Treatment

In certain cases of bacterial conjunctivitis, the doctor prescribes antibiotic tablets as an alternative or in addition – for example, necessary in patients in whom a bacterial infection in other parts of the body has spread to the eyes. This can happen especially in the case of a chlamydia infection or a gonococcal infection – two known venereal diseases. In such cases, the sexual partner should also be treated with antibiotics to prevent the couple from re-infecting each other.

Even if conjunctivitis symptoms improve before this happens, be sure to use the antibiotics for as long as the doctor has recommended. Otherwise, some bacteria may remain in the body and multiply again after stopping the treatment and cause conjunctivitis again.

Viral conjunctivitis: treatment

In contrast, the therapy for viral conjunctivitis consists of symptom-relieving measures such as cold compresses on the eyes (see: Conjunctivitis – Home Remedies). Artificial tears dripped into the eye can also relieve the symptoms.

In severe viral conjunctivitis, eye drops containing corticosteroids (“cortisone” eye drops) can be used for a short time to reduce inflammation. In the long term, however, these are not suitable for therapy because they suppress the body’s own defenses. This can delay healing and promote an additional bacterial infection (then the doctor prescribes antibiotic-containing eye drops).

In the case of an eye infection with herpes simplex viruses, eye drops containing cortisone must not be used under any circumstances, because this could aggravate the infection and lead to serious complications.

Allergic conjunctivitis: treatment

As with viral conjunctivitis, cold compresses and tear substitutes can reduce the symptoms of allergic conjunctivitis.

Eye drops containing antihistamines (anti-allergic agents) serve the same purpose: Often, sufficient improvement can be achieved with over-the-counter preparations. If not, the doctor can prescribe more potent antihistamine eye drops. Alternatively or additionally, he may prescribe eye drops containing anti-inflammatory and analgesic NSAIDs (such as Ketorolac) and/or mast cell stabilizers (such as Azelastine). The latter, like antihistamines, have an antiallergic effect.

In persistent cases of allergic conjunctivitis, short-term use of cortisone-containing eye drops may be helpful. However, a herpes simplex infection of the eyes must be ruled out beforehand.

Other forms of conjunctivitis: treatment

Whether foreign bodies, contact lenses, or sun exposure are the causes of conjunctivitis, treatment always consists of removing or avoiding the trigger. For example, foreign bodies or corrosive substances in the eye are flushed out as quickly and completely as possible, contact lenses are removed, and further UV radiation is avoided.

Depending on the cause, further treatment measures may be useful. For example, in the case of conjunctivitis due to dry eyes, tear substitutes (e.g. with hyaluronic acid) can alleviate the symptoms. They moisten the eye and keep it moist. Eye drops with hyaluronic acid provide additional moisture, because the substance binds water.

Home remedies for conjunctivitis

For example, you can put cool compresses on the closed eyes, such as a cold quark pad. It can help against the itching and burning of the eye and also has a decongestant and anti-inflammatory effect. Many people also use certain medicinal plants for an eye compress. For example, eyebright and calendula are valued for their anti-inflammatory properties.

Before using home remedies, you should first see an ophthalmologist so that he can determine the cause and severity of conjunctivitis and prescribe any necessary medication. Otherwise, you may be at risk of worse damage to your eye!

You can read more about home remedies for conjunctivitis and how to use them in the article Conjunctivitis – Home Remedies.

Home remedies have their limits. If the symptoms persist over a longer period of time, do not get better or even get worse, you should always consult a doctor.

Irritations of various kinds can lead to conjunctivitis. Doctors distinguish between two groups:

Infectious conjunctivitis: This is caused by bacteria, viruses, fungi or parasites. This form of conjunctivitis is contagious.
Non-infectious conjunctivitis: This includes all cases of conjunctivitis that are not caused by pathogens but by, for example, allergies or mechanical irritants.

Below you will find more detailed information on the development of the main forms of conjunctivitis.

Bacterial conjunctivitis

The most common triggers of bacterial conjunctivitis are:

Staphylococcus aureus
Streptococcus pneumoniae
Haemophilus species

Another bacterial cause of inflamed conjunctiva can be bacteria of the type Neisseria gonorrhoeae (“gonococci”). Then it is a gonococcal conjunctivitis.

Infection with both chlamydia and gonococcus very often manifests as venereal disease (in the case of gonococcus called gonorrhea or gonorrhea). Transmission of the germs into the eyes – either those of the infected person or those of another person – is possible, for example, in the case of poor hand hygiene or via (shared) towels.

In addition, pregnant women infected with gonococci and/or chlamydia in the genital area can transmit the germs to the newborn during birth, during passage through the infected birth canal. As a result, conjunctivitis may develop in the baby – called neonatal conjunctivitis (or ophthalmia neonatorum).

Viral conjunctivitis

Viral conjunctivitis is acute. Sometimes it occurs in the context of a cold – triggered by cold viruses (such as rhinoviruses). The pathogens can also spread to the conjunctiva of the eyes in other viral diseases affecting the whole body (systemic), such as measles, mumps, rubella and chickenpox viruses.

Sometimes, however, the viral infection is confined to the eye (i.e., does not also affect the rest of the body). Such localized viral conjunctivitis is usually caused by adenoviruses, of which there are several types (serotypes). Most often, types 5, 8, 11, 13, 19 and 37 are responsible for adenovirus conjunctivitis. It is often severe. In about a quarter of cases, corneal inflammation (keratitis) also develops. Such a simultaneous corneal and conjunctival inflammation caused by adenoviruses is called keratoconjunctivitis epidemica.

A less common cause of viral conjunctivitis is enteroviruses. Acute hemorrhagic conjunctivitis develops in this case. It is accompanied by bleeding under the conjunctiva and occurs in Africa and Asia.

Conjunctivitis caused by fungi or parasites

Fungal infections are very rarely the cause of conjunctivitis. Such fungal conjunctivitis can be caused, for example, by Candida or Microsporum fungi or molds of the genus Aspergillus.

Also rarely, infestation by parasites leads to inflamed conjunctiva. This can happen, for example, with Loa Loa – a form of threadworm disease (filariasis). Conjunctivitis can also develop as part of an infection with Leishmania (leishmaniosis) or trypanosomes.

Allergic conjunctivitis

Allergic conjunctivitis is a type I allergic reaction (immediate type). This means that the hypersensitivity reactions (eye itching, tearing, etc.) occur within a few minutes or even seconds after contact with the specific allergen. Three forms of disease are distinguished:

Seasonal allergic conjunctivitis.

It is also called hay fever conjunctivitis. Triggers of this form of conjunctivitis are mold spores or pollen from trees, grasses or other plants that enter the eye through the air. Depending on the life cycle of the plant in question, seasonal allergic conjunctivitis is mainly noticeable in spring, late summer or early fall.

Atopic conjunctivitis

Keratoconjunctivitis vernalis

This combined corneal and conjunctival inflammation is most likely allergic in origin and usually occurs in the spring. In autumn and winter, the symptoms subside. It most commonly affects male children and adolescents between five and 20 years of age who have eczema, asthma, or seasonal allergy.

Other forms of conjunctivitis

In addition to allergy triggers, there are other possible causes of non-infectious conjunctivitis:

For example, irritation of the eyes by chemical, physical, thermal stimuli or radiation is often behind it, such as a chemical burn or burn of the eyes, makeup, dust, smoke, wind, drafts, wind, cold, UV light (sun, solarium), and welding. Contact lenses worn too long or damaged, as well as ocular strain (e.g. concentrated close work or lack of sleep) can also irritate the conjunctiva to such an extent that it becomes inflamed.

extended screen work (with infrequent blinking).
hormonal or metabolic disorders, e.g. during pregnancy, estrogen therapy (such as during menopause), diabetes mellitus or thyroid disorders
certain eye diseases such as a dysfunction of the meibomian glands (sebaceous glands in the eyelid), disorders of the lacrimal glands or ectropion (outward turning of the eyelid)
certain other diseases such as Sjögren’s syndrome, rheumatoid arthritis, acne, rosacea
Medications such as acetylsalicylic acid (ASA), beta-blockers or hormonal contraceptives that suppress ovulation (ovulation inhibitors)

Adjacent pathological processes such as a malignant tumor of the meibomian glands (meibomian gland carcinoma) can also result in conjunctivitis.

Is conjunctivitis contagious?

Viral or bacterial conjunctivitis is very contagious. You can reduce the risk of infection with the following tips:

Hand washing: Frequent, proper hand washing and hand sanitizing will reduce the number of germs on your fingers.
Your own towel: Use your own towel or, even better, disposable towels that you dispose of directly after use. This will protect other household members from contracting conjunctivitis.
No handshaking: Even if it seems unkind – refrain from shaking hands if you have conjunctivitis. Even if you avoid it – unconsciously you often grab your eyes, so that a germ transmission via the hands can happen quickly.
Do not share eye drops: If you use eye drops (any eye drops) – do not share them with other people.

Conjunctivitis: examination and diagnosis

This is followed by eye examinations: Using a slit-lamp examination, the doctor can examine the front part of the eye for signs of conjunctivitis (possibly with involvement of the cornea = keratoconjunctivitis).

Careful folding of the eyelids can reveal inflammation – this leaves typical marks on the inside of the eyelids. Small foreign bodies that may be present in the eye can also often be discovered in this way. For patients, this examination is rarely really unpleasant.

Depending on the suspected cause, further examinations may be necessary for clarification. For example, if wetting disorders are suspected, the Schirmer test can help. The tear secretion is determined with a filter paper strip in the conjunctival sac.

A swab from the conjunctiva can show whether and – if so – which pathogens are the cause of an infectious conjunctivitis.

Conjunctivitis: course and prognosis

Infectious conjunctivitis usually heals without consequences – and often no medication is necessary. However, in some infections – especially those with certain bacteria – the inflammation can persist for a long time (possibly become chronic) or cause complications if left untreated.

Chlamydial conjunctivitis, for example, can develop as a so-called trachoma, especially under poor hygienic conditions, and may then lead to progressive scarring of the conjunctiva. This can limit the eyesight up to blindness! In fact, trachoma is the most common cause of acquired blindness worldwide.

In the case of gonococcal conjunctivitis, early treatment is also very important. Otherwise, there is a risk of visual impairment and even blindness if the cornea is involved.

In the case of non-infectious conjunctivitis, the prognosis depends largely on whether and how well the trigger can be eliminated or avoided (for example, in the case of allergic or foreign body-related conjunctivitis). In the case of conjunctivitis due to injury (such as burns or chemical burns), the severity of the eye damage also plays a role.