Conjunctivitis: what it is, symptoms and treatment

By Cristiano Antonino On Apr 17, 2023

Conjunctivitis is the most common eye inflammation, and the main reason why you go to the ophthalmologist. In fact, it affects the tissue most exposed to external agents, the external mucous layer that covers the sclera of the eye

And, accordingly, the inner part of the eyelid.

The eye affected by conjunctivitis, be it viral or bacterial, appears red

The person may feel burning, itching, and/or pain, and increased tearing may occur.

In the morning, it may be difficult to open the eye due to the presence of mucopurulent secretions, and the white part of the eye (sclera) may swell.

As a rule, conjunctivitis is easy to resolve.

However, a timely visit to the doctor or ophthalmologist is needed to start the right therapy.

Conjunctivitis: what it is and what are its causes

As the name suggests, conjunctivitis is an inflammatory process that affects the conjunctiva (mucous membrane that covers the eyeball and the inside of the eyelids).

When this comes into contact with a virus or a bacterium, but also following allergic reactions, contact with irritating or toxic substances or due to a dysfunction of the tear film, it becomes inflamed, therefore edema is generated, the blood vessels are more evident (hyperemia) and in general there is a redness of the eyeball.

Conjunctivitis can be of origin:

bacterial
viral
allergic
irritating

The most common is bacterial conjunctivitis, usually caused by Staphylococcus aureus, Streptococcus pneumoniae or Haemophilu.

Viral conjunctivitis is due, in most cases, to adenovirus and is usually bilateral and more or less symmetrical.

When ocular involvement is unilateral, it is usually due to herpes simplex (the virus of cold and genital herpes) or to herpes zoster, the main etiological agent of shingles.

Allergic conjunctivitis, common especially during spring, is caused by an allergy to pollen or grasses, but it can also be due to contact with an animal’s fur or the use of inappropriate cosmetics.

Finally, irritative conjunctivitis is caused by direct contact between the eye and an irritant agent (chemical, caustic or corrosive products, small objects, eyelashes, dust).

Depending on the type of conjunctivitis you get, the symptoms can vary.

Symptoms of conjunctivitis

The most common symptoms are:

burning and/or pain in the eyes
red eyes
eye fatigue
eyelid swelling
itching
increased tearing
eye dryness
eye secretion
entropion (inward rotation of the eyelid margin)

Acute bacterial conjunctivitis (as well as viral conjunctivitis) causes hyperemia, tearing, irritation, discharge and foreign body sensation: symptoms that affect only one eye but soon spread to the other.

The patient generally feels an itchy sensation, as the secretion contains pus: the eye, especially in the morning, is sticky as if the eyelids were “glued”.

Bacterial conjunctivitis and viral conjunctivitis resolve in a few days although there may be aftermaths of up to 3-4 weeks, following adequate therapy, but they can give rise to some complications when they spread to the cornea and are caused by chlamydia or gonorrhea.

Risk factors include frequent contact with infected individuals, use of contact lenses, upper respiratory tract infections and seasonal influenza, and venereal disease.

In particular, bacterial conjunctivitis is frequent in children and young people and in those who work in a poorly hygienic environment, and is transmitted very easily (even by sharing a towel); viral conjunctivitis is instead frequent during exanthematous diseases, flu and when you contract herpes.

Allergic conjunctivitis is characterized by particularly intense itching, tearing and photophobia (you feel discomfort when you are exposed to sunlight).

It usually affects both eyes, is never contagious and can occur seasonally if the subject is sensitive to allergens present only at certain times of the year.

Finally, irritative conjunctivitis can be caused by chlorinated water, detergents, foreign bodies in the eye, smoke, fumes or eyelashes rubbing against the conjunctiva.

Symptoms are very similar to those of bacterial or viral conjunctivitis, but there is no purulent discharge

If many of the symptoms are common (redness of the eyes, tearing, photophobia), there are instead symptoms characteristic of specific forms: allergic conjunctivitis is characterized by itching, swelling and the presence of follicles; viral conjunctivitis is often accompanied by an enlargement of the submandibular and preauricular lymph nodes; bacterial conjunctivitis often causes a greenish-yellow discharge to leak, which makes the eye sticky.

Conjunctivitis: the diagnosis

In both adults and children, conjunctivitis must be promptly diagnosed: if its cause is immediately determined, it is possible to follow a therapeutic course that leads to the complete resolution of the problem in a few days.

The ophthalmologist, to detect the presence of conjunctivitis and to determine its type, after a careful history (analysis of symptoms) goes and carries out an eye check.

Through the use of specific optical instruments, you are able to evaluate the degree of eye redness, the seriousness of the situation, the depth of the infection and the possible presence of skin rashes or bullous lesions in the margin of the eyelids.

If deemed appropriate, you can take a small sample of the secretion in order to conduct a histological investigation, thus identifying the pathogen responsible for the conjunctivitis.

It is essential that a differential diagnosis is carried out, in order to distinguish conjunctivitis from other diseases with similar symptoms (uveitis, keratoconjunctivitis, keratitis, etc.), and to identify whether it is viral or bacterial conjunctivitis, or rather an allergic or irritating.

How to cure conjunctivitis

The treatment for conjunctivitis depends on the cause that led to the inflammation.

Bacterial and viral conjunctivitis usually resolve spontaneously within a few days, but in severe cases it can last up to a month.

If the ophthalmologist does not deem it necessary to administer medicines, it is sufficient to follow simple rules of conduct: do not use contact lenses until the symptoms have completely disappeared (it is necessary to throw away the previously used lenses), gently cleanse the eyes with medicated gauze, use artificial tears, always wash your hands after eye contact. If drug therapy is necessary, the doctor can prescribe antibiotics (in the form of eye cream or eye drops) in the case of bacterial conjunctivitis, or antiviral drugs in the case of viral conjunctivitis usually caused by adenoviruses and herpesviruses.

Allergic conjunctivitis can be treated with antihistamines, anti-inflammatories and decongestants, in rare cases with corticosteroids.

Again, it is essential to avoid using contact lenses and rubbing your eyes, as well as (if possible) not exposing yourself to the responsible allergen.

Finally, irritative conjunctivitis resolves itself by avoiding the use of the substance that caused it.

This solution is valid both if it is caused by detergents, perfumes or cosmetics, and if the cause is due to overexposure to sunlight, the use of contact lenses or exposure to fumes or other physical agents.

How to prevent conjunctivitis

While it can’t always be avoided, conjunctivitis can be prevented by taking some precautions.

To avoid the risk of infective conjunctivitis it is essential:

wash your hands often with soap and water, avoiding touching your eyes if they are not perfectly sanitized
change the towels and pillowcase regularly

If you contract the infection, it is important:

do not rub the good eye after touching the infected eye
discard cosmetics used during the early stages of the infection
do not apply make-up
do not wear contact lenses
avoid close contact with other people
do not use medicines that have expired or have been open for more than 7 days
do not touch the infected eye with the eye drop applicator
contact the ophthalmologist and avoid treating yourself, as the use of non-indicated drugs could lengthen healing times and give rise to complications
contact the specialist if for more than 2-3 days a strong redness of the eye is observed and typical symptoms are felt (photosensitivity, pain, itching, burning, difficulty keeping the eye open, unusual secretions, vision problems, enlarged lymph nodes around the eye)

If you suffer from allergic conjunctivitis you should avoid:

keep the windows open and drive with the windows down during pollen season
stand in the freshly cut grass
play outdoor sports

Effective precautions for both allergic and irritant conjunctivitis include:

brush your hair often after being outdoors, because they could retain pollen
air the rooms often
maintain a temperature in the house below 20°C
avoid smoky and dusty environments
wear sunglasses
avoid contact with irritants
remove all possible dust receptacles (carpets, wallpapers, dried flowers, etc.)
wash sheets and pillowcases regularly at 50°C
clean the house frequently with a water vacuum cleaner or one equipped with a HEPA filter

The neonatal form

Conjunctivitis can also affect newborns and very young children.

There are chemical neonatal conjunctivitis (due to topical prophylaxis, and spontaneously resolved in 48-96 hours after exposure to the agent) and bacterial conjunctivitis that affect the newborn from 4 days to several weeks after birth, but it is possible that the child also suffers of two particular types of conjunctivitis:

from chlamydia
gonococcal

Chlamydial conjunctivitis in the newborn usually appears 5-14 days after birth: it often involves mucopurulent secretions and conjunctival hyperemia, but severe eyelid edema may also occur.

Gonococcal conjunctivitis, on the other hand, appears 2-5 days after birth, and is caused by Neisseria gonorrhoeae (generally contracted by the newborn during passage through the birth canal, if infected, or in the uterus through ascending infection).

Also characterized by the latter by eyelid edema, mucopurulent secretions and conjunctival chemosis, it must be treated promptly as – if neglected – it can lead to corneal blindness.

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