Is the conjunctivitis contagious?

Introduction

The conjunctiva of the eye is a transparent layer of mucous membrane, which among other things has an important defence function. The conjunctivitis, the so-called conjunctivitis, is contagious or noncontagious, depending on the cause. One speaks of an infectious and a non-infectious conjunctivitis.

A conjunctivitis that is caused by an allergy or an autoimmune disease or external influences is not contagious. External influences can be cigarette smoke, chlorine or dust, for example. However, if the conjunctiva becomes inflamed due to bacteria, viruses, fungi or parasites, it is contagious.

Depending on age, the condition of the body’s own defence system and other factors, the risk of conjunctivitis is different. The doctor can often deduce the cause of conjunctivitis from the medical history, a doctor-patient conversation. In the case of a non-infectious conjunctivitis, the eye usually does not secrete any secretion.

Instead, in the infectious form, secretion can be observed, which can vary depending on the trigger. In addition, characteristic accompanying symptoms indicate the type of inflammation. A foreign body sensation, itching and burning of the eyes indicate that conjunctivitis is probably not contagious.

In contrast, swollen lymph nodes on the neck are a sign of infectious conjunctivitis. In general, however, it is not possible for the patient to distinguish between infectious and non-contagious conjunctivitis on the basis of the symptoms. To avoid infection it is important to wash the hands after each contact with the eyes or face and to disinfect them thoroughly afterwards. A visit to an ophthalmologist is advisable, as he or she is best able to assess the cause of the infection and the associated risk of infection, and to take targeted countermeasures with the right therapeutic measures (therapy of conjunctivitis).

Is the conjunctivitis very contagious?

Conjunctivitis caused by external stimuli such as dust or dirt, allergies, fatigue, injuries, preservatives in eye drops, UV light, drafts, cigarette smoke, foreign bodies in the eye (including contact lenses), rheumatic diseases or dryness of the eye are not contagious. If conjunctivitis is caused by bacteria, fungi, parasites or viruses, it is highly infectious. If one eye is affected first, there is a high probability that the other eye will also become infected.

The triggers usually get into the eye by smear or droplet infection. Most contagious bacterial conjunctivitis is caused by staphylococci, especially the so-called Staphylococcus aureus. Haemophilus influenzae causes conjunctivitis especially in children.

Chlamydia is transmitted during sexual intercourse. They can also get into the eye through bath water. This is called swimming pool conjunctivitis, but it is less common.

In addition, the infected mother can transmit the chlamydia to the child during birth. In the same way, gonococcus can cause conjunctivitis in the infant. But these occur less frequently compared to chlamydia.

Triggers for viral conjunctivitis can be so-called adenoviruses. They often cause febrile infections that are accompanied by extremely contagious conjunctivitis. Conjunctivitis caused by herpes viruses is also highly contagious and the surrounding skin areas can also be affected.

In addition, viral conjunctivitis caused by chickenpox, rubella and measles is highly contagious. Conjunctivitis caused by fungi only occurs in immunocompromised persons. With a healthy immune system, the risk of fungal infection is low. Parasites, such as some worms or fly larvae, can also cause infectious conjunctivitis. However, this occurs less frequently in European countries, but is problematic in tropical, African areas and Central and South America.