Attack rates are highest in winter and early spring. It occurs often during or after an upper respiratory infection. Onset is characterized by malaise, myalgias, arthralgias, fever, chills and sometimes diarrhea. These symptoms may resolve over one to three days or may lead to erythematous macular lesions over the extremities, often with purpura. There can be tachypnea, tachycardia, or mild hypotension and the syndrome can progress to meningitis with confusion, headache, and nuchal rigidity.
Blood cultures are usually positive and the syndrome responds promptly to high-dose penicillin.
Sometimes this presentation is self-limited, the organism being isolated on blood culture after the patient has begun recovery. Onset is sudden and progression is rapid. High fever, shaking chills, weakness, severe muscle tenderness, dizziness, headache, and petechiae occur. The petechiae are often found on the oral mucosa and the conjunctiva. The skin lesions coalesce to purpura or purpura fulminans.