A study published by The British Medical Journal (BMJ) identifies important differences between current monkeypox symptoms and previous outbreaks in endemic regions.
The findings are based on 197 confirmed cases of monkeypox at a London infectious disease center between May and July 2022.
Some of the common symptoms they describe, including rectal pain and swelling of the penis (edema), differ from those described in previous outbreaks.
As such, the researchers recommend that clinicians consider monkeypox infection in patients presenting with these symptoms, saying those with confirmed infection and presenting with extensive penile lesions or severe rectal pain.”should be valued for ongoing review or inpatient treatment».
According to government data, as of July 18, 2022, there were 2,137 confirmed cases of monkeypox in the UK. Of these, 2,050 were in England and almost three quarters (73%) were in London.
The 197 participants in this study were men (mean age 38 years), of whom 196 identified as gay, bisexual, or other men who have sex with men. All patients presented lesions on the skin or mucous membranes, most commonly on the genitals or in the perianal area.
The majority (86%) of patients reported systemic disease (affecting the entire body). The most common systemic symptoms were fever (62%), swollen lymph nodes (58%), and muscle aches and pains (32%).
And in contrast to existing case reports suggesting that systemic symptoms precede skin lesions, 38% of patients developed systemic symptoms after the onset of lesions mucocutaneous, while 14% presented lesions without systemic characteristics.
A total of 71 patients reported rectal pain, 33 sore throat, and 31 penile edema, while 27 had oral lesions, 22 had a solitary lesion, and 9 had swollen tonsils.
The authors note that solitary lesions and swollen tonsils were not previously known as typical features of monkeypox infection and could be confused with other conditions.
Just over a third (36%) of the participants also had HIV infection and 32% of those screened for sexually transmitted infections had a sexually transmitted infection.
Overall, 20 (10%) of the participants were hospitalized for treatment of symptoms, most commonly rectal pain and penile swelling. However, no deaths were recorded and no patients required intensive care in hospital.
Only one participant had recently traveled to an endemic region, confirming ongoing transmission within the UK, and only a quarter of patients had known contact with someone with confirmed monkeypox infection, raising the possibility of transmission by people without symptoms or with very few.
The authors acknowledge some limitations, such as the observational nature of the findings, the potential variability of clinical record keeping, and the fact that the data is limited to a single center.
However, they say these findings confirm the unprecedented ongoing community transmission of monkeypox virus among gay men, bisexual men and men who have sex with men in the UK and many other non-endemic countries.
They write: “Understanding these findings will take important implications for contact tracing, public health advice, and ongoing infection control and isolation measures.” And they demand ongoing research to inform infection control and isolation policies and guide the development of new diagnostics, treatments and preventive measures.