Clinical Features

Respiratory diphtheria presents as a sore throat with low-grade fever and an adherent membrane of the tonsils, pharynx, or nose. Neck swelling is usually present in severe disease. Cutaneous diphtheria presents as infected skin lesions which lack a characteristic appearance. 

Incidence

Approximately 0.001 cases per 100,000 population in the U.S. since 1980; before the introduction of vaccine in the 1920s incidence was 100-200 cases per 100,000 population. Diphtheria remains endemic in developing countries. The countries of the former Soviet Union have reported >150,000 cases in an epidemic which began in 1990.
Complications Myocarditis, polyneuritis, and airway obstruction are common complications of respiratory diphtheria; death occurs in 5%-10% of respiratory cases. Complications and deaths are much less frequent in cutaneous diphtheria. 

Transmission

Direct person- to-person transmission by intimate respiratory and physical contact. Cutaneous lesions are important in transmission. 

Risk Groups

In the pre-vaccine era, children were at highest risk for respiratory diphtheria. Recently, diphtheria has primarily affected adults in the sporadic cases reported in the U.S. and in the large outbreaks in Russia and New Independent States of the Former Soviet Union.  
 
Date: October 6, 2005
Content source: National Center for Immunization and Respiratory Diseases: Division of Bacterial Diseases