The conjunctiva is a thin membrane that partially covers the inner eyelid. If the conjunctiva is inflamed, the first signs of disease are itching, red eyes and pain. The course is usually harmless, but prolonged or untreated conjunctivitis can lead to complications.
Conjunctivitis overview
The function of the conjunctiva is to distribute the tear fluid across the surface of the eyes. If it is inflamed, this manifests as itching, burning or reddened eyes.
Although conjunctivitis (pink eye) caused by bacteria or viruses is harmless in most cases, anyone who suspects having conjunctivitis should seek medical advice from an ophthalmologist, not least to obtain a clear diagnosis and appropriate treatment.
Conjunctivitis is one of the most common eye conditions worldwide and can affect people of all ages. Children are particularly at risk, as their immune systems are not yet fully developed. Whether conjunctivitis is contagious or not, and which treatment options are used, depends on the cause of the inflammation.
Conjunctivitis often begins in one eye, but can very quickly spread to both eyes, for example, by rubbing the eyes without thinking. It usually takes 5 to 12 days from the time of infection until the first conjunctivitis symptoms appear. The symptoms of acute conjunctivitis last for about one to two weeks.
Conjunctivitis can go away on its own, but to be on the safe side, you should consult a doctor so as not to prolong the disease’s course unnecessarily. In the worst case, complications can occur, which can have serious consequences if the inflammation is left untreated.
Types of conjunctivitis
A distinction must be made between acute and chronic conjunctivitis and between infectious and non-infectious forms of inflammation.
Acute and chronic conjunctivitis
- Acute conjunctivitis: symptoms appear sharply and suddenly, but do not last long.
- Chronic conjunctivitis: eye redness and other symptoms last longer, but are less pronounced.
Infectious and non-infectious conjunctivitis
- Infectious conjunctivitis: infectious conjunctivitis is usually caused by microorganisms, such as bacteria or viruses, and is contagious.
- Non-infectious conjunctivitis: in addition to infectious conjunctivitis, there is also a non-infectious form of conjunctivitis. As the name suggests, it is not contagious.
Special forms of conjunctivitis
- Koch-Weeks conjunctivitis: a mucopurulent form of conjunctivitis that occurs particularly south of the equator.
- Gonococcal conjunctivitis: a purulent conjunctivitis that can cause damage to the cornea. If left untreated, the symptoms of this conjunctivitis can lead to blindness.
- Trachoma: this form of inflammation of the conjunctiva is triggered by certain bacteria and affects both eyes. This infection is the world’s most common eye illness. It can lead to blindness and should be treated by a doctor at an early stage.
- Ocular pemphigoid: this is not conjunctivitis, but an autoimmune disease that can, however, cause inflammation of the conjunctiva. It can lead to the connective tissue both shrinking and scarring. In particular, older people are affected by this form of inflammation of the conjunctiva.
Causes
There are various causes, depending on the type of conjunctivitis. Viral or bacterial infections and allergic reactions are the most common causes of conjunctivitis. However, UV radiation or foreign bodies in the eye can also lead to conjunctivitis.
Infectious conjunctivitis
There are numerous possible bacterial and viral pathogens of conjunctivitis. While viruses such as adenoviruses or herpes viruses are the predominant causes of conjunctivitis in adults, in infants and children it is more likely to be caused by bacteria such as streptococci, pneumococci, staphylococci or chlamydia. Parasites are also rarely the cause of infectious conjunctivitis. There are many possible transmission routes for this type of conjunctivitis, including:
- Rubbing your eyes: this allows pathogens to get onto the hands, which can cause others to become infected, for example, by shaking hands or touching the same objects.
- Talking, coughing or sneezing: conjunctivitis can also be transmitted by droplet infection.
- Infection in the birth canal: if an expectant mother suffers from conjunctivitis, the newborn can become infected with conjunctivitis pathogens in the birth canal.
- Dirty contact lens cases: contact lens cases must always be kept clean. Otherwise, pathogens that cause conjunctivitis may accumulate in the contact solution.
Non-infectious conjunctivitis
There are not only numerous causes for infectious conjunctivitis, but also for non-infectious forms of conjunctivitis, including:
- External stimuli: dust, dirt, smoke, chlorinated water and injuries can trigger non-infectious conjunctivitis.
- Lack of tear fluid: if the eye surfaces become dry, tissue damage or conjunctivitis can occur.
- Allergies: whether due to medication, pollen or other allergens, as soon as eye irritation occurs, conjunctivitis can follow.
- Fungus: certain fungi, such as Candida or Aspergillus, can trigger conjunctivitis.
Symptoms
The main symptoms of conjunctivitis are red eyes, burning or itching, a feeling of a foreign body in the eye and increased tearing. Eyelid movement can also cause pain. Additionally, it can lead to sticky eyes.
Conjunctivitis often causes the eyes to release a secretion that can temporarily lead to blurred vision. While this is watery or white in viral or allergic conjunctivitis, bacterial conjunctivitis usually causes a purulent secretion.
In some cases, conjunctivitis can lead to complications such as inflamed eyelids or swollen lymph nodes. If these symptoms occur, patients should seek medical examination to avoid more serious complications.
By the way: due to the typical eye redness it causes, conjunctivitis is often referred to as ‘pink eye’. The redness is caused by increased blood circulation and the protrusion of blood vessels in the conjunctiva.
Diagnosis
Conjunctivitis is diagnosed based on the typical symptoms and by means of an eye examination. With the help of a slit lamp, the ophthalmologist illuminates different areas of the eye and then assesses the greatly magnified details. Among other things, the examination determines whether swelling or injuries are present and whether the eye is secreting fluids.
The type of secretions can provide information as to whether the conjunctivitis is viral or bacterial. This distinction is particularly important because the different forms of conjunctivitis require different treatment plans.
In bacterial conjunctivitis, the pathogen can be detected with an eye swab. Following the swab, a rapid antigen test can show whether there are adenoviruses in the sample taken, which pose a particularly high risk of infection.
As a next step, the secretion sample can be examined in the laboratory, where the precise conjunctivitis pathogen can be identified. This is particularly relevant if there is a suspicion that the patient is affected by a specific form of conjunctivitis.
If allergic conjunctivitis is suspected, allergy tests are carried out to identify the triggering allergen.
Treatment
The type of treatment for conjunctivitis depends on the cause.
Treatment: allergic conjunctivitis
Anti-allergy eye drops are used for allergic conjunctivitis. It is also important for patients to change their behaviour: triggering allergens should be avoided.
Treatment: bacterial conjunctivitis
Bacterial conjunctivitis can be treated with antibiotic eye drops.
Treatment: viral conjunctivitis
When it comes to viral conjunctivitis, the focus is on alleviating the symptoms, as there are no causative medications for the majority of viruses that cause conjunctivitis. Treatment with antiviral ointments or eye drops is only suitable for a few types of viruses, such as herpes viruses.
Eye drops containing cortisone are used to help with blurred vision or light sensitivity. Patients can also soothe their irritated eyes themselves with a few simple remedies: a warm (or cold) facecloth placed on the eye area can reduce unpleasant itching and tightness.
Prevention
Infectious conjunctivitis is often highly contagious. Hygiene measures such as hand washing, avoiding physical contact and using separate towels can help prevent transmission. Frequent hand disinfection can also prevent conjunctivitis from spreading from one eye to the other, or from infecting other people.
By the way: certain viruses can survive on metal and plastic surfaces for a very long time – sometimes longer than a month. It is therefore advisable to disinfect surfaces that you have come into contact with.
What is the quickest way to combat conjunctivitis?
Quick and efficient relief from conjunctivitis depends on its cause. Antibiotic eye drops help with bacterial conjunctivitis, while anti-allergy eye drops help with allergic conjunctivitis. A home remedy, such as a hot or cold damp facecloth, can reduce eye itching and redness.
Should you stay at home if you have conjunctivitis?
In the case of infectious conjunctivitis, it is advisable to stay at home, as the illness is contagious. By using your own towels, you can prevent other people from getting infected. In this way, you are actively helping ensure that your fellow human beings stay healthy.
How do I know if I have conjunctivitis?
Typical symptoms of conjunctivitis are reddened eyes, itching, foreign body sensation, increased tearing and secretions. If redness and sticky eyelids occur, those affected should consult an ophthalmologist for diagnosis.
Can conjunctivitis heal on its own?
Many cases of acute conjunctivitis heal on their own, particularly viral or allergic forms. In the case of bacterial conjunctivitis or severe symptoms, however, treatment by an ophthalmologist is important to prevent complications such as corneal damage.