Bacterial conjunctivitis (eye conjunctivitis)

Conjunctivitis, the medical term for conjunctivitis, has chemical, traumatic, toxic, fungal, viral, bacterial or allergic causes. Common features of all types of conjunctivitis include pain, redness and an eye discharge, while visual acuity is usually unaffected or only mildly affected. Bacterial conjunctivitis occurs in approximately 30% of patients with conjunctivitis. The treatment of the eye condition is done through antibiotics and/or self-care measures, which usually produces excellent results. However, untreated bacterial conjunctivitis can lead to serious vision complications in some situations.

  • Causes and risk factors bacterial conjunctivitis
  • Symptoms: Lots of discharge from the eyes
  • Diagnosis and examinations
  • Treatment via antibiotics or supportive
  • Complications
  • Prognosis of conjunctivitis is excellent

Causes and risk factors bacterial conjunctivitis

Bacterial conjunctivitis is most common in individuals without additional health problems. Risk factors include exposure to infected patients, contact with shared products (such as towels or the door handle), sinusitis, patients with a weakened immune system, pre-existing eye disease, trauma, recent eye surgery, and exposure to an STD at birth. Contact lens wearers are also at increased risk of developing bacterial conjunctivitis, especially if they continue to wear contact lenses while sleeping, practice improper contact lens hygiene, do not replace contact lenses in a timely manner and/or expose contact lenses to water. Furthermore, overcrowded living conditions, such as in a primary school or barracks, also contribute to the faster development of bacterial conjunctivitis.

Bacterial conjunctivitis sometimes causes blurred vision / Source: Nufkin, Flickr (CC BY-2.0)

Symptoms: Lots of discharge from the eyes

Acute conjunctivitis

Bacterial conjunctivitis is always bilateral (present in both eyes). When gonococci (coffee bean-shaped bacteria) cause eye inflammation, this is medically referred to as gonorrheal conjunctivitis. The symptoms start very quickly and the patient loses an excessive amount of discharge (mucus and sometimes pus) from the red-looking eye. This is usually thick but can be thin (watery, watery eyes). In addition, this eye inflammation causes swelling of both the conjunctiva (chemosis, conjunctival edema) and the eyelid (swollen eyelids), with the appearance of bags under the eyes being possible. Burning pain, itchy eyes and light aversion (photophobia) are other typical symptoms of the bacterial eye infection. In addition, some patients suffer from variable vision, or have blurred vision.

Subacute and chronic conjunctivitis

Less acute or subacute purulent (purulent) conjunctivitis with moderate discharge is due to organisms such as Haemophilus influenzae and Streptococcus pneumoniae . In chronic conjunctivitis, a mild purulent discharge often occurs in combination with less serious eye-related symptoms. Common organisms for this are the staphylococcal bacteria Staphylococcus aureus and Moraxella lacunata .

Diagnosis and examinations

Eye examination

During an eye examination, the ophthalmologist suspects a bacterial form of conjunctivitis if it is accompanied by a pus-shaped discharge. The rapidity of onset combined with the severity of the discharge is useful in determining the underlying organism. Bacterial conjunctivitis often produces much more mucus and pus than viral conjunctivitis. Finally, the ophthalmologist notices swollen lymph nodes just in front of the ear.

Differential diagnosis

It is sometimes confusing for a doctor to make a diagnosis based on the patient’s presenting set of symptoms. The following conditions constitute the differential diagnosis for bacterial conjunctivitis:

  • acute angle-closure glaucoma (increased intraocular pressure may result in damage to the optic nerve, resulting in vision loss)
  • allergic conjunctivitis
  • blepharitis (inflammation of the eyelid margins)
  • chemical burns
  • dry eyes
  • a squamous cell carcinoma (form of skin cancer), conjunctival
  • a subconjunctival hematoma (bleeding under the eye conjunctiva)
  • episcleritis (inflammation between the conjunctiva and sclera)
  • pharyngoconjunctival fever
  • iritis (inflammation of the iritis accompanied by a lot of eye pain and hypersensitivity to light)
  • keratoconjunctivitis
  • scleritis (severe inflammation of the hard sclera)
  • toxic and chemical conjunctivitis
  • Anterior uveitis (eye inflammation of ciliary body and iris), granulomatous
  • viral conjunctivitis

Treatment via antibiotics or supportive

Acute bacterial conjunctivitis

The treatment of acute bacterial conjunctivitis is done with a topical (applied to the skin) antibiotic (administered as eye drops or as an ointment). The patient uses the eye drops with correct eye drop guidelines. Occasionally, an oral (taken by mouth) antibiotic is required. The ophthalmologist prescribes penicillin for gonococcal conjunctivitis, which also reduces the patient’s risk of developing a corneal injury as a result of the inflammation of the conjunctiva. However, an ophthalmologist is sometimes critical when prescribing antibiotics, because the eye disease is often self-limiting, meaning that the patient recovers spontaneously. An antibiotic does not (always) shorten the duration of the symptoms. Cool compresses and artificial tears are other supportive treatments that also relieve symptoms.

Subacute and chronic conjunctivitis

The doctor often treats subacute and chronic conjunctivitis with a topical (local) broad-spectrum antibiotic such as chloramphenicol. If this treatment does not work, the ophthalmologist will take a smear of the eye discharge to investigate the exact cause of the eye irritation. For example, sometimes the symptoms of contact lens wearers with conjunctivitis have an allergic rather than a bacterial cause. In this target group, it is also wise for the patient to temporarily refrain from wearing contact lenses during treatment with antibiotics.


Complications of bacterial conjunctivitis range from mild to severe. Corneal irritation may cause dry eyes, a corneal ulcer and/or symblepharon (growth between the mucous membrane of the eyelids and the mucous membrane of the eyeball), resulting in (partial) loss of vision. These complications often only occur with highly pathogenic bacteria such as Chlamydia trachomatis or Neisseria gonorrhoeae .

Prognosis of conjunctivitis is excellent

The prognosis of bacterial conjunctivitis is excellent, with most patients making a full recovery within one to two weeks thanks to a course of antibiotics. Patients with isolated bacterial conjunctivitis do not die, but sometimes a patient does have an underlying disease that causes death. For example, sepsis (blood poisoning) and meningitis (meningitis with headache, fever and stiff neck) caused by N. gonorrhoeae are life-threatening conditions.

read more

  • Neonatal conjunctivitis: Conjunctivitis in babies
  • Conjunctivitis: Inflammation of the eye conjunctiva
  • Viral conjunctivitis: Inflammation of the conjunctiva caused by a virus
  • Allergic conjunctivitis (eye conjunctivitis): Types