Clinical features

  • Pharyngitis: the bacteria make a toxin that kills healthy tissues in the respiratory system. Within 2-3 days, the dead tissue forms a thick, grey coating that can build up in the throat or nose “pseudomembrane.” It can cover tissues in the nose, tonsils, voice box, and throat, making it very hard to breathe and swallow.

  • C. diphtheriae usually localizes in the upper respiratory tract, ulcerates the mucosa, and induces the formation of an inflammatory pseudomembrane

  • A membrane typically develops on one or both tonsils, with extension to the tonsillar pillars, uvula, soft palate, oropharynx, and nasopharynx. C. diphtheriae multiplies on the surface of the mucous membrane, resulting in the formation of the “pseudomembrane”

  • Myocarditis

  • Polyneuritis

  • Cutaneous


  • PCR of throat swab (tox gene) - but can have severe disease even if toxA gene is not expressed

  • Gram stain?

  • Elek test (for toxin detection - gene expression?)


  • Diphtheria Anti-Toxin - DAT (passive immunisation) - antibodies (made from blood plasma of horses that have been immunised against diphtheria toxin - neutralises toxins produced by the bacteria - anaphylaxis (2-10%?)

  • Antibiotic (penicillin, erythromycin)


  • Toxoid vaccine (+ booster) (doesn't affect carriage)

  • Passive immunity from mother after birth

  • Contact tracing

  • Antibiotics for eradication of carriage