The disease begins suddenly with fever, malaise, and sore throat. A characteristic feature is a thick, gray tonsillar exudate is present and may spread rapidly to cover the tissues of the throat around the tonsils, the uvula, soft palate, rear wall of the throat, and the larynx. The exudate is tenacious and not easily removed. The patient appears very ill, pale, lethargic, and weak. There may be significant stridor.
Diphtheria is potentially fatal, and mortality increases with delay in diagnosis.
The suspicion of diptheria by the clinical appearance of the patient should be enough to begin treatment. Treatment should be undertaken in consultation with an infectious disease specialist. An antitoxin is given, along with intravenous penicillin in high doses. Complications include nerve paralysis. Other important and dangerous complications are airway obstruction and myocarditis, which carry a high mortality.