What are the symptoms of diphtheria?

Symptoms of Diphtheria

Diphtheria primarily presents as an upper-respiratory tract illness characterized by sore throat, low-grade fever, and an adherent gray-colored pseudomembrane of the tonsil(s), pharynx, and/or nose. 1

Primary Clinical Manifestations

• Sore throat is a hallmark symptom, often the first indication of infection 1
• Low-grade fever commonly accompanies the infection 1
• The most distinctive feature is the development of a gray-colored pseudomembrane that is firmly adherent to the mucosa lining the:
  • Nasopharynx 1
  • Tonsils 1
  • Pharynx 1
  • Larynx 1
  • Nose 1

Progression and Complications

• Extension of the pseudomembrane into the trachea-bronchial tree can cause life-threatening airway obstruction 1
• Systemic absorption and dissemination of diphtheria toxin can lead to serious complications 1:
  • Cardiac complications (toxin-mediated myocarditis) 1, 2
  • Neurologic complications (toxin-mediated neuropathy) 1, 2

Clinical Course

• Initial symptoms may resemble an influenza-like illness 3, 4
• The disease can progress rapidly, particularly in unvaccinated individuals 5
• Hoarseness of voice may develop as the infection progresses 5
• Neck swelling due to cervical lymphadenopathy may be present 4
• In severe cases, breathing difficulties can develop as the pseudomembrane expands 3

Risk Factors for Severe Disease

• Age: higher mortality rates in children under 5 years and adults over 40 years 3
• Vaccination status: unvaccinated or inadequately vaccinated individuals are at highest risk 1
• Delayed treatment: mortality increases with delayed administration of antitoxin 4

Clinical Variants

• Respiratory diphtheria is the most common and dangerous form 1, 2
• Cutaneous diphtheria can also occur but is not reportable in the United States 1

Important Clinical Considerations

• The pseudomembrane is the most distinctive clinical feature and should prompt immediate consideration of diphtheria 1
• The membrane may appear white or grayish and is firmly adherent to the underlying tissue 5
• Attempting to remove the membrane may cause bleeding 2
• Symptoms can progress rapidly, with potential for fatal outcomes if not treated promptly 5
• Heart rhythm problems may develop as a complication of toxin absorption 3

Early recognition of these symptoms is critical as prompt treatment with diphtheria antitoxin and appropriate antibiotics significantly improves outcomes 4, 5.