What is the treatment for diphtheria?

Treatment for Diphtheria

The treatment for diphtheria requires immediate administration of diphtheria antitoxin (DAT) followed by appropriate antibiotic therapy, primarily erythromycin or penicillin, along with supportive care for airway management. 1, 2

Immediate Management

1. Diphtheria Antitoxin (DAT)

• Must be administered as soon as diphtheria is suspected, without waiting for laboratory confirmation 1, 2
• DAT neutralizes circulating toxin but cannot reverse damage already done to tissues
• Available through CDC's Emergency Operations Center (770-488-7100) 1
• Dosage depends on the extent and duration of disease:
  • Pharyngeal or laryngeal disease of 48 hours: 20,000-40,000 units
  • Nasopharyngeal lesions: 40,000-60,000 units
  • Extensive disease of 3+ days duration or swelling of the neck: 80,000-100,000 units
• Prior to administration, patients should be tested for sensitivity to horse serum 1

2. Antibiotic Therapy

• Erythromycin (oral or IV) is the preferred antibiotic 3
  • Adults: 1g/day divided into multiple doses for 7-10 days
  • Children: 40 mg/kg/day divided into multiple doses for 7-10 days
• Alternative: Benzathine penicillin G (single IM injection) 1
  • Adults: 1,200,000 units
  • Children <6 years: 600,000 units
• Antibiotics eliminate the organism, stop toxin production, and prevent transmission 1, 2

3. Supportive Care

• Airway management is critical - intubation or tracheostomy may be necessary for respiratory obstruction 2
• Cardiac monitoring for signs of myocarditis
• Neurological assessment for signs of neuropathy
• Fluid and electrolyte management

Management of Close Contacts

1. Culture: All close contacts should have throat and nasopharyngeal samples taken for culture 1

2. Antimicrobial Prophylaxis: All close contacts should receive prophylaxis regardless of vaccination status 1

   • Erythromycin: 40 mg/kg/day for children, 1g/day for adults for 7-10 days, OR
   • Benzathine penicillin G: 600,000 units IM (children <6 years), 1,200,000 units IM (≥6 years)

3. Vaccination: 1

   • Contacts with incomplete vaccination should receive immediate dose of diphtheria toxoid
   • Contacts with complete primary series but no booster in past 5 years should receive a booster dose

Clinical Pitfalls and Caveats

• Delayed treatment increases mortality: Early administration of DAT is critical as effectiveness decreases with time 4
• Misdiagnosis risk: Diphtheria can be misdiagnosed as severe strep throat, viral pharyngitis, or infectious mononucleosis 5, 6
• Pseudomembrane recognition: The characteristic grayish adherent membrane may not always be visible without careful examination 1, 2
• Cardiac complications: Myocarditis can develop 1-2 weeks after onset, requiring close monitoring 5
• Neurological complications: Peripheral neuropathy may develop 2-8 weeks after infection 7
• Follow-up cultures: Carriers should have follow-up cultures after completing antimicrobial therapy 1

Special Considerations

• Cutaneous diphtheria: Treatment approach depends on toxigenicity 1

  • For toxigenic strains: Same approach as respiratory diphtheria
  • For non-toxigenic strains: Routine contact investigation not necessary

• Pregnancy: Erythromycin is preferred over tetracyclines for pregnant women 3

• Vaccination status: Even vaccinated individuals can develop milder forms of disease, though with significantly reduced risk 1, 2

The timely administration of both DAT and appropriate antibiotics is essential for reducing mortality from diphtheria, with studies showing that delayed treatment significantly increases the risk of fatal outcomes 4, 5.