According to the authors of the largest international case series to date, monkeypox can often present as anorectal pain or a single genital lesion and can easily be misdiagnosed as a sexually transmitted infection (STI)
Of the more than 500 infections diagnosed, mainly in men who have sex with men (MSM), 95% had rash, 73% had anogenital lesions, and 41% had mucosal Mary Queen of London University’s Chloe Orkin, MD, and colleagues report.
In addition, 15% of patients had anorectal pain, and 10% had pain in the genital area, according to New England Journal of Medicine findings.
“The current international case definition needs to be expanded to add symptoms that are not currently included, such as oral ulcers, anal mucosal ulcers and single ulcers,” Orkin said in a statement. “These specific symptoms can be severe and lead to hospitalization, so making a diagnosis is important.”
Distinct presentations such as isolated genital skin lesions and lesions on the palms and soles of the feet can be considered by the researchers. It can lead to misdiagnosis of syphilis and other sexually transmitted infections (such as herpes), which can delay testing.
“Expanding the case definition will help doctors more easily identify the infection, thereby preventing people from passing it on,” Orkin continued. “Given global constraints on vaccine and antiviral supplies for this chronically underfunded, neglected tropical infection, prevention remains a key tool to limit global spread.”
The analysis includes 4 Between June 27 and June 24, 528 people were diagnosed in 16 countries. Overall, 98 percent were MSM—the study sample included nine heterosexual men with monkeypox. The median age was 38, three-quarters were white, 41 percent had HIV, and the vast majority were well controlled. Clinically, the presence of HIV infection did not significantly affect the emergence of monkeypox, the researchers said.
Of the 61 people found, 26 developed oropharyngeal symptoms, including pharyngitis, dysphagia, epiglottitis, and oral or tonsil lesions, the researchers noted. In three individuals, the initial symptoms were lesions of the conjunctival mucosa.
The research team noted extensive skin lesions with multiple simultaneous stages, which were described as vesicular pustules in 58% of the studies. Regarding the number of lesions, although 39% of patients had fewer than five lesions, the number of lesions increased over time, with or without systemic features. Rash accompanied or preceded systemic symptoms, including fever (62%), lethargy (41%), myalgia (31%), and headache (27%); lymphadenopathy was also common, affecting 56%.
Monkeypox transmission is suspected to occur through sexual activity in 95% of cases – a theory that yields “primary genital, anal and oral mucosal lesions, which may represent the site of inoculation,” The author pointed out. Potential risk factors include numerous sexual partners, recent international travel, and participation in large gatherings or live sex venues.
Notably, 29% of testers reported concomitant STIs. The researchers urge clinicians to consider monkeypox in high-risk groups with traditional STI symptoms.
“It is important to stress that monkeypox is not a sexually transmitted infection in the traditional sense,” said co-author John Thornhill, MD, PhD, also of Queen Mary University. “It can be acquired through any form of close physical contact. However, our work shows that, to date, most transmission has been associated with sexual activity — primarily but not limited to men who have sex with men.”
While viral DNA was present in semen samples from 29 of the 32 people tested, “this could be accidental, as we don’t know if it’s high enough to facilitate sexual transmission,” Thornhill added. “More work needs to be done to better understand this.”
How long the virus remains contagious after the lesion clears remains unclear, the researchers said, adding that the UK Health Safety Authority guidelines recommend using condoms for 8 weeks after infection.
Overall, 5% of people in the study received antiviral therapy, most commonly cidofovir or tecovir (Tpoxx); 13% were hospitalized, mainly Because of severe anorectal pain and repeated soft tissue infections. Overall, “the clinical outcomes of this case series are reassuring,” the researchers wrote. “Most cases were mild and self-limited, with no deaths.”
Nine percent of patients reported having been vaccinated against smallpox, but the data were too limited to comment, the team noted
Limitations of the study include that symptom-driven enrollment may have missed asymptomatic or mildly symptomatic people, and that HIV-infected individuals may be overrepresented due to HIV, the researchers said. Referral to the clinic.
Kate Kneisel is a freelance medical journalist based in Belleville, Ontario.
Disclosures were not reported at the time of publication.