Clinical Presentation

The prodrome of fever, headache, backache, and fatigue begins one to two weeks after exposure to the virus. The cutaneous eruptions last 14 to 21 days and are usually all in the same stage. The lesions evolve from macules, to papules, vesicles, pustules and crusts. The cutaneous lesions of monkeypox are very similar to smallpox, but unlike smallpox, most patients with monkeypox have pronounced lymphadenopathy involving cervical, submandibular, postauricular (photograph left), and inguinal nodes. Following desquamation, approximately half of the patients will have hypopigmentation and/or hyperpigmentation for up to two years. The severe scarring seen in smallpox is rare. The case fatality rate for monkeypox varies. It is extremely low in patients who were previously vaccinated against smallpox. In unvaccinated children the fatality rates are 10 to 15%.

The major differential diagnosis is with chickenpox. Varicella-zoster virus infection is a milder disease with smaller, superficial lesions in various stages of evolution.