Practice Alert

Monkeypox: What FPs need to know, now

Author and Disclosure Information

Here’s how to distinguish monkeypox from other exanthems and what to do if you suspect it in your patient.



The Centers for Disease Control and Prevention (CDC) and the World Health Organization are investigating an outbreak of monkeypox cases that have occurred around the world in countries that do not have endemic monkeypox virus.1,2 As of July 5, there have been 6924 cases documented in 52 countries, including 560 cases that have occurred in the United States.2 In the United States, as well as globally, a large proportion of cases have been in men who have sex with men.

First, what is monkeypox? Monkeypox is an orthopox virus that is closely related to variola (smallpox) and vaccinia (the virus used in the smallpox vaccine). It is endemic in western and central Africa and is contracted by contact with an infected mammal (including humans). Transmission can occur through direct contact with infected body fluids or lesions, via infectious fomites, or through respiratory secretions (although this usually requires prolonged exposure).

What is the disease course? The incubation period is 4 to 17 days. The initial symptoms include fever, malaise, headache, sore throat, and lymphadenopathy. A rash erupts 1 to 4 days after the prodrome and progresses synchronously from macules to papules to vesicles and then to pustules, which eventually scab over and fall off. In some cases reported in the United States, the rash started in the groin and genital area.

Don’t be fooled by other exanthems. Monkeypox can be confused with chickenpox and molluscum contagiosum (MC). However, the lesions in chickenpox appear asynchronously (all 4 stages present at the same time) and the papules of MC contain a central pit.

Can monkeypox be prevented? There are currently 2 vaccines against orthopox viruses: ACAM2000 and Jynneos. Currently, these vaccines are routinely recommended only for those at occupational risk of orthopox exposure.3

What you should know—and do. Be alert for any patient who presents with a suspicious rash; if there is a possibility of monkeypox, the local public health department should be contacted. They will investigate and collect samples for laboratory testing and will elicit contact names and locations. If monkeypox is confirmed, they may offer close contacts 1 of the 2 vaccines, which if administered within 4 days of exposure can prevent infection.

Advise all patients confirmed to have monkeypox to self-isolate until all skin lesions have healed. Good infection control practices in the clinical setting will prevent spread to staff and other patients.

More information about monkeypox, including images of typical lesions—as well as an update on the current investigation in the United States and worldwide—can be found on the CDC website.4

Next Article: