Conjunctivitis (Pink Eye): Causes, Symptoms and Treatments

Viral conjunctivitis is very easily spread between people, so it’s important to keep good hand hygiene, avoid rubbing your eyes then touching anything or anyone, and keep your distance from people if you are coughing or sneezing. Bacterial conjunctivitis can also spread by direct contact, and from one eye to the other. Allergic conjunctivitis is not contagious.

How long does conjunctivitis last

How long does conjunctivitis last

The duration of conjunctivitis, or pink eye, largely depends on the underlying cause - whether it’s viral, bacterial, or allergic.

Viral Conjunctivitis

This is the most common type of conjunctivitis and is usually caused by adenoviruses, which are also responsible for common colds. If left untreated, viral conjunctivitis typically lasts from 1 to 2 weeks. The symptoms, such as redness, tearing, and irritation, may peak within the first few days and gradually subside as the immune system clears the virus. Although treatment isn't required for the infection to resolve, supportive care like lubricating eye drops can help alleviate discomfort during this period. However, viral conjunctivitis is highly contagious, so avoiding close contact with others and maintaining good hygiene is crucial.

Bacterial Conjunctivitis

Caused by bacteria like Staphylococcus aureus or Streptococcus pneumoniae, bacterial conjunctivitis can last anywhere from 2 days to 2 weeks if untreated. In many cases, the body's immune system can eventually clear the infection without antibiotics, but symptoms like pus-filled discharge, redness, and irritation might persist longer without treatment. Moreover, untreated bacterial conjunctivitis can lead to more severe complications, such as corneal ulcers, which could threaten vision.

Allergic Conjunctivitis

Unlike viral and bacterial forms, allergic conjunctivitis is not infectious and is triggered by allergens like pollen, dust mites, or pet dander. The duration of allergic conjunctivitis varies based on exposure to the allergen. If untreated and the allergen exposure continues, symptoms like redness, itching, and watery eyes can persist indefinitely until the allergen is removed or managed. Antihistamines or other allergy medications can help control symptoms more quickly.

How long does conjunctivitis last after treating?

The duration of conjunctivitis, or pink eye, after starting treatment depends on the type of conjunctivitis and the effectiveness of the treatment administered.

Viral Conjunctivitis

Even with treatment, viral conjunctivitis typically runs its course within 1 to 2 weeks. While antiviral medications are generally not effective against most forms of viral conjunctivitis, supportive treatments—such as lubricating eye drops, cold compresses, and good hygiene practices—can help manage symptoms and speed up recovery. The symptoms usually begin to improve within a few days of starting these supportive measures, though the virus must still run its natural course. Although treatment can make the patient more comfortable, it won’t significantly shorten the duration of the infection.

Bacterial Conjunctivitis

Bacterial conjunctivitis usually improves more rapidly with appropriate antibiotic treatment. With antibiotic eye drops or ointment, symptoms often begin to improve within 24 to 48 hours. Most cases of bacterial conjunctivitis clear up completely within 5 to 7 days of starting treatment. It’s important to complete the full course of antibiotics prescribed, even if symptoms disappear before finishing the medication, to ensure that the infection is fully eradicated and to prevent recurrence.

Allergic Conjunctivitis

The duration of allergic conjunctivitis can vary depending on the persistence of the allergen exposure and the effectiveness of the treatment. Antihistamine eye drops (such as those containing sodium cromoglicate) or oral antihistamines typically provide relief from symptoms within a few hours to a few days. If allergen exposure is minimised or eliminated, symptoms usually resolve quickly. However, if exposure continues, symptoms may persist despite treatment, though they are generally more manageable.

What is the treatment of conjunctivitis?

The treatment of conjunctivitis has three main goals:

1. To reduce eye discomfort.
2. To reduce or lessen the course of the infection or inflammation.
3. To prevent the spread of the infection in contagious forms of conjunctivitis.

The appropriate treatment for conjunctivitis depends on its cause:

In bacterial conjunctivitis, this is usually treated with antibiotic eye drops or ointments. Improvement can occur after three or four days of treatment, but the entire course of antibiotics needs to be used to prevent recurrence.

With viral conjunctivitis there are no available drops or ointments to treat the virus for this type of conjunctivitis and antibiotics will not cure a viral infection. Like a common cold, the virus just has to run its course, which may take up to two or three weeks in some cases. The symptoms can often be relieved with cool compresses and artificial tear solutions. For the worst cases, topical steroid drops may be prescribed to reduce the discomfort from inflammation, but do not shorten the course of the infection. Fortunately, most cases of viral conjunctivitis clear quite quickly by themselves.

In allergic conjunctivitis, the first step should be to remove or avoid the irritant, if possible. Cool compresses and artificial tears sometimes relieve discomfort in mild cases and in more severe cases, antihistamines either oral or eye drops may be recommended. Cases of persistent allergic conjunctivitis may also require topical steroid eye drops.

For most cases, gentle thorough cleansing is enough to clear an eye infection. For children under the age of 2 years or for mild cases in adults, you may want to first try using freshly boiled and cooled water and a clean flannel.

Gently wipe over the eyelids starting from the outer edge of the lashline with eyelid closed and sweep inwards and downwards towards the inner corner near the nose. This can help clear crusting and debris in the eyes and eyelashes safely. Repeat every two to four hours, for up to 48 hours, and a cool flannel may also be useful to soothe itchy or irritated eyes.

Antibiotic eye drops or ointments are available to buy for adults and children over 2 years old to treat bacterial conjunctivitis, but should be reserved for more severe or prolonged cases. Those under 2 years old need a prescription from their doctor.

Conjunctivitis usually clears up without any medication. See you doctor if symptoms haven’t improved after a couple of weeks. Antibiotics are not usually required for conjunctivitis, but your doctor may consider them under certain circumstances, including if a sexually transmitted infection such as chlamydia could be the cause.

If you suspect an allergy is to blame, keep a symptom diary to identify the trigger and try antihistamine drops from the pharmacy.

If your vision is affected such as if it's consistently reduced in one eye, you feel very sensitive to light, lights look hazy, or you see wavy lines or flashing lights, you should seek urgent attention from your doctor, 111 or an Emergency Department. Similarly, if the pain is deep and intense, especially if you wear contact lenses, this is another reason to seek urgent attention.

If your baby is less than 28 days old and experiencing a red eye or discharge, see your doctor urgently for assessment.

If you feel well and your work does not require close contact with others, you can go to work with conjunctivitis. Your child can go to school or nursery if they are well. If you have reason to believe something more serious is going on with your eyes, you should seek urgent medical attention.