Human monkeypox: cutaneous lesions in 8 patients in Canada.

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Date: Oct. 3, 2022
From: CMAJ: Canadian Medical Association Journal(Vol. 194, Issue 38)
Publisher: CMA Impact Inc.
Document Type: Clinical report
Length: 1,933 words
Lexile Measure: 1990L

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Most patients with human monkeypox (HMPX) have cutaneous lesions. In the 2022 outbreak of HMPX across nonendemic countries, cutaneous lesions have been different than previously described. (1,2) In this outbreak, primary lesions often occur at anogenital and oral sites, suggesting direct inoculation, similar to patterns observed with syphilis. (3) Primary lesions may occur before, with or without the onset of systemic symptoms. Although secondary lesions continue to present in a disseminated fashion, developmental pleomorphism (the phenomenon of lesions at different stages of development at the same anatomic site), is seen more commonly than previous outbreaks in which lesions were classically monomorphic. (4) Furthermore, new lesions can continue to emerge for several days. (4,5) The lesions may resemble those caused by other infections including syphilis, herpes simplex virus, molluscum contagiosum or folliculitis. (5)

We present clinical images to show the breadth of cutaneous and mucocutaneous lesions that presented in 8 patients with HMPX (confirmed by real-time polymerase chain reaction) who were cared for in Toronto, Canada, from May to July 2022. None of these patients were notably immunocompromised by a condition (including uncontrolled HIV) or immunosuppressing medication, which may modify disease severity. Patients with well-controlled HIV are indicated accordingly in the captions. We include images of active primary lesions at common locations (Figure 1, Figure 2, Figure 3 and Figure 4) and of lesions showing developmental pleomorphism (Figure 5 and Figure 6). We also include images of active secondary lesions by stage of development, including macules, papules, pustules, umbilicated pustules and ulcers that then scab over and heal (Figure 7, Figure 8, Figure 9, Figure 10 and Figure 11). We provide images of lesions on the palms and soles (Figure 6 and Figure 9). In several cases, patients initially received diagnoses of, and were treated for, probable syphilis or herpes simplex virus before a differential diagnosis of HMPX was considered.


(1.) Jezek Z, Szczeniowski M, Paluku KM, et al. Human monkeypox: clinical features of 282 patients. J Infect Dis 1987;156:293-8.

(2.) Fenner F, Henderson DA, Arita I, et al. Human monkeypox virus and other poxvirus infections of man. In: Smallpox and its eradication. Geneva: World Health Organization; 1988:1297.

(3.) Magnuson HJ, Thomas EW, Olansky S, et al. Inoculation syphilis in human volunteers. Medicine (Baltimore) 1956;35:33-82.

(4.) Thornhill JP, Barkati S, Walmsley S, et al. Monkeypox virus infection in humans across 16 countries--April-June 2022. N Engl J Med 2022;387:679-91.

(5.) Sukhdeo SS, Aldhaheri K, Lam PW, et al. A case of human monkeypox in Canada. CMAJ 2022;194:E1031-35.

Competing interests: Darrell Tan reports research support from Abbvie, Gilead and Glaxo Smith Kline. Sharmistha Mishra is supported by a Tier 2 Canada Research Chair in mathematical modelling and program science. No other competing interests were declared.

This article has been peer reviewed.

The authors have obtained patient consent.

Affiliations: Department of Medicine (Sukhdeo, Tan, Mishra), University of Toronto; Division of Infectious Diseases (Tan, Mishra), MAP Centre for Urban Health Solutions (Tan,...

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Gale Document Number: GALE|A721424904