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Dermatology Guide to Diagnosing Monkeypox

As monkeypox makes its way around the United States, more undiagnosed cases may be turning up in dermatology offices as patients can mistake the disease’s characteristic rash for other dermatologic conditions.

Here’s a primer to help dermatology professionals diagnose monkeypox.

At a Glance: What Is Monkeypox?

• Monkeypox is a rare, communicable disease caused by the monkeypox virus, which comes from the same family as the variola virus, which causes smallpox¹
• The main characteristic of monkeypox is rash with lesions that are firm or rubbery, deep-seated, and well-circumscribed^2,3
• Monkeypox lesions often, but not always, occur in the genital areas, anorectal areas, or the mouth²
• There are multiple stages to the lesions caused by monkeypox: macular, papular, vesicular, pustular, and scabs^2,3

Monkeypox can spread via close or personal contact with an infected individual. In addition to coming into direct contact with the rash, scabs, or bodily fluids from an infected individual, transmission can occur through respiratory secretions and by touching objects that have been in contact with an infected person. Research is still needed to determine if monkeypox can be spread before a person exhibits symptoms.⁴

The incubation period is 3 to 17 days, during which a person will not have symptoms.² The primary sign of monkeypox is the characteristic rash associated with monkeypox lesions (pustules).^2,3 The lesions are firm or rubbery, deep-seated, well-circumscribed, and will often develop a depression in the top (umbilication). During this current outbreak, lesions often, but not always, occur in the genital areas, anorectal areas, or the mouth.²

Patients may describe the lesions as painful until they start to heal and feel itchy. The rash may be confined to an area as small as a few lesions or a single lesion and may not be spread to multiple sites on the skin. The rash may sometimes appear on the palms of the hands and the soles of the feet of an infected patient. Rectal symptoms, such as purulent or bloody stools or rectal bleeding, have been frequently reported in the current outbreak. Fever and other prodromal symptoms may occur before or after the rash appears. In a minority of cases, fever is not present at all.²

There are 4 main stages to monkeypox lesions: macular, papular, vesicular, and pustular. While the first 3 stages all typically last 1 to 2 days, pustules will typically last 5 to 7 days before crusting over and forming scabs. Scabs remain for approximately 1 to 2 weeks before falling off. Illness typically lasts 2 to 4 weeks in total. A person is no longer contagious when all scabs have fallen off and have been replaced by a new layer of skin.²

A diagnosis of monkeypox should be considered for any patient who exhibits symptoms consistent with monkeypox. The Centers for Disease Control and Prevention urges anyone who is believed to have been exposed to monkeypox to initiate a risk assessment with their state health department. These patients should be advised to isolate themselves at home and avoid close contact with people and animals until a diagnosis is confirmed.⁵

Dermatologists may want to consider adding a monkeypox screener for patients who call seeking appointments when they have symptoms consistent with the disease.

References

1. Centers for Disease Control and Prevention. About monkeypox. Updated July 22, 2022. Accessed August 9, 2022. https://www.cdc.gov/poxvirus/monkeypox/about.html
2. Centers for Disease Control and Prevention. Clinical recognition: key characteristics for identifying monkeypox. Updated August 5, 2022. Accessed August 9, 2022. https://www.cdc.gov/poxvirus/monkeypox/clinicians/clinical-recognition.html
3. Centers for Disease Control and Prevention. Case definitions for use in the 2022 monkeypox response. Updated July 22, 2022. Accessed August 9, 2022. https://www.cdc.gov/poxvirus/monkeypox/clinicians/case-definition.html#suspect
4. Centers for Disease Control and Prevention. Monkeypox:  how it spreads. Updated July 29, 2022. Accessed August 9, 2022. https://www.cdc.gov/poxvirus/monkeypox/transmission.html
5. Centers for Disease Control and Prevention. Clinician FAQs. Updated August 11, 2022. Accessed August 22, 2022. https://www.cdc.gov/poxvirus/monkeypox/clinicians/faq.html#Advice-for-Monkeypox-Patients-to-Reduce-Transmission