Rectal pain, penile swelling more common in current monkeypox outbreak

Common symptoms of monkeypox virus such as rectal pain and penile swelling (oedema) differ from those described in previous outbreaks and are more prevalent, according to a study. The study, published by The BMJ, identifies important differences in monkeypox symptoms between the current outbreak and previous outbreaks in endemic regions.

For the study, researchers from Guys and St Thomas' NHS Foundation Trust included 197 men with confirmed monkeypox cases at an infectious disease centre in London between May and July 2022.

Of the total, 196 identified as gay, bisexual, or other men who have sex with men.

Overall, 20 (10 per cent) of participants were admitted to hospital for the management of symptoms, most commonly rectal pain and penile swelling. The researchers recommend that clinicians consider monkeypox infection in patients presenting with these symptoms.

Those with confirmed monkeypox infection with extensive penile lesions or severe rectal pain "should be considered for ongoing review or inpatient management", said Aatish Patel from the Trust.

All patients presented with lesions on their skin or mucosal membranes, most commonly on the genitals or in the perianal area.

Most (86 per cent) of patients reported systemic illness (affecting the entire body). The most common systemic symptoms were fever (62 per cent), swollen lymph nodes (58 per cent), and muscle aches and pain (32 per cent).

And in contrast with existing case reports suggesting that systemic symptoms precede skin lesions, 38 per cent of patients developed systemic symptoms after the onset of mucocutaneous lesions, while 14 per cent presented with lesions without systemic features.

A total of 71 patients reported rectal pain, 33 sore throat, and 31 penile oedema, while 27 had oral lesions, 22 had a solitary lesion, and 9 had swollen tonsils.

The researchers also noted that solitary lesions and swollen tonsils were not previously known to be typical features of monkeypox infection, and could be mistaken for other conditions.

Just over a third (36 per cent) of participants also had HIV infection and 32 per cent of those screened for sexually transmitted infections had a sexually transmitted infection.

However, no deaths were reported and no patients required intensive hospital care.

"Understanding these findings will have major implications for contact tracing, public health advice, and ongoing infection control and isolation measures," Patel said.

The authors also acknowledge some limitations, such as the observational nature of the findings, the potential variability of clinical record keeping, and the fact that the data are limited to a single centre.

However, they said these findings confirm the ongoing unprecedented community transmission of monkeypox virus among gay, bisexual, and other men who have sex with men seen in the UK and many other non-endemic countries.