A new study from Israel describes 26 cases of misdiagnosed mpox. Of the 26, 6 patients (23%) who were given a diagnosis of bacterial tonsillitis, 6 (23%) primary syphilis, 5 (19.2%) oral or genital herpes, and 4 (15.3%) bacterial proctitis or anal abscess. The study was published in the International Journal of Infectious Diseases.
The study highlights how easily the disease was misdiagnosed during the initial months of a global outbreak that saw the virus spread in countries where it has never or rarely been detected. This is the first outbreak in many countries driven by sexual transmission among men who have sex with men (MSM) and not international travel.
The case-patients were all diagnosed between May and October of this year, and all were MSM. All patients said that during their first visit with a doctor, they were not asked about contact with an mpox patient. Of the 26 patients, 17 (65.3%) were on HIV prophylaxis, and 5 (19.2%) were HIV positive.
The average interval between missed and right diagnosis was 4.4 days.
"MPX infection may be easily overlooked and be confused with other diseases, mainly other STIs [sexually transmitted infections]. Due to the nature of its transmission, and its non-classical presentation of lesions concentrated in the anogenital areas in about 75% of the patients, it is most commonly confused with other STIs such as syphilis and genital herpes simplex infection" the authors said.