Trachoma

Introduction

Trachoma is an infection of the eyes by a bacterium Chlamydia trachomatis. It is the leading preventable cause of blindness worldwide and very contagious.
The organism is found in the conjunctival as well as corneal epithelium and is responsible for two different conditions:

  1. Trachoma (a severe disease)
  2. Inclusion conjunctivitis (milder)

Trachoma is commonly associated with poverty and unhygienic living conditions.

Clinical features

Acute phase:

  • Irritable red eye
  • Mucopurulent eye discharge
  • Eyelid oedema, pain, photophobia in severe cases

Chronic phase:

  • Follicles on tarsal conjunctivae
  • Papillae
  • Superficial punctate keratitis

End stage:

  • Pannus formation on superior cornea
  • Corneal scarring
  • Eyelid scarring with trichiasis, entropion
  • Conjunctival scarring
  • Limbal scarring with Herbert’s pits

Differential diagnoses

  • Other forms of infective conjunctivitis (especially viral)
  • Allergic/vernal conjunctivitis
  • Corneal scarring from other diseases

Complications

  • Trichiasis
  • Entropion
  • Corneal scarring

Investigations

  • Conjunctival scraping for microscopy
  • Immunofluorescence or ELISA test
  • Giemsa staining for trachoma inclusion bodies

Drug treatment

Topical:

Tetracycline ointment applied 4 times a day for 6 weeks

Systemic:

Erythromycin, tetracycline (not) recommended for young children) or then ewer antibiotics e.g. azithromycin as appropriate
Azithromycin

  • Adult: 500 mg orally once daily for 3 days
  • Child:
    • over 6 months: 10 mg/kg (maximum 500 mg) orally once daily for 3 days;
    • over 6 months (body weight 15-25 kg) 200 mg once daily for 3 days;
    • body weight 26-35 kg: 300 mg once daily for 3 days;
    • body weight 36-45kg: 400 mg once daily for 3 days

Surgical treatment

  • Indicated for the treatment of trichiasis, entropion, corneal scarring
  • Corneal graft, but entropion must be corrected first

Caution and contraindications

  • Systemic tetracycline is contraindicated in young children

Prevention

  • Improve personal and public hygiene
  • Treat the whole community with topical or systemic antibiotics
  • Prompt surgery for trichiasis and entropion to prevent blindness from corneal scarring