Differential diagnoses - Conjunctivitis and iritis in pictures

Dr Nigel Stollery offers advice on differentiating between allergic and infective eye conditions and provides advice on management.

Acute iritis


  • Painful inflammation of the iris
  • Uncommon in children – can be acute, chronic or relapsing
  • May be associated with other conditions, such as rheumatoid arthritis, Behçet’s disease, malignancy, trauma to eye, infection


  • Usually requires referral to secondary care
  • Treatment is usually with steroid eyedrops and cycloplegic drops
  • Dark glasses may be helpful if there is photophobia
  • Oral analgesia, such as paracetamol, can be beneficial
  • Chronic cases may require immunosuppressant medication

Viral conjunctivitis


  • Common condition (more common than bacterial form)
  • Presents with pink conjunctiva and dilated blood vessels
  • Not usually associated with pain, photophobia or visual disturbance
  • Discharge unusual, although the eye may water excessively
  • Often associated with a viral URTI


  • A benign, self-limiting condition
  • Antibiotics are of little help
  • Cold compresses may be beneficial

Bacterial conjunctivitis


  • Benign condition caused by infection of the conjunctiva
  • Common (can occur at any age) and may be unilateral or bilateral
  • Conjunctiva become red and inflamed, with dilated blood vessels, but not usually painful
  • Discharge usually present and tends to be thick


  • Usually managed in primary care or by pharmacist
  • Bathing helpful in removing the discharge
  • Topical antibiotic ointment or eyedrops can help
  • If diagnosis is in doubt, swabs can be helpful

Allergic conjunctivitis


  • Irritation of conjunctiva by allergen, such as pollen
  • Both eyes usually affected – rapid onset after exposure
  • Eyes usually itchy, with red or pink appearance
  • Eyelids may swell and there may be a burning sensation
  • Pain, photophobia and visual disturbance not usually present


  • Antihistamine drops can help
  • Patient should avoid allergens and rubbing the eyes
  • Bathing with cold water can be of benefit
  • In severe cases, steroid eyedrops may be required

Dr Nigel Stollery is a GP in Leicestershire

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