Atypical case of monkeypox with multiple bacterial skin superinfection.

Here we present an interesting case of monkeypox infection characterized by cellulitis surrounding the vesicles and multiple sites of the lesions. A 52-year-old Caucasian MSM (men who have sex with men) presented in September 2022 to the Infectious Disease Unit of AOUP “P. Giaccone” University Hospital in Palermo, Italy, because of the onset of skin lesions, high fever, and systemic symptoms 4 days prior. He reported multiple previous sexual intercourses, as well as unprotected anal sexual intercourse, 14 days ago with a partner who later tested positive for monkeypox virus (MPXV). The physical examination revealed 10 skin lesions, including one on the dorsal surface of the right hand and the rest on the back, anogenital region, right thigh, buttock, and groin. The lesion first appeared on the right hand and glans before spreading throughout the body. In some instances, the lesions were pustules with central umbilication and crusted scabs. Bacterial cellulitis was diagnosed due to the presence of significant edema, erythema, and pain in the hand (Figure 1a), thigh (Figure 1b), and buttock. The results of routine blood tests were unremarkable except for C-reactive protein of 32.2 mg/l (normal <5 mg/l). Given the suspicion of monkeypox, pustule, nasopharynx, urethra, rectum, blood, and urine samples were collected, and a real-time polymerase chain reaction (PCR) assay was performed. Positive PCR results for MPXV were observed in swabs, blood, and urine samples. Screening for other sexually transmitted infections was negative. Seven days of empiric treatment with 100 mg of doxycycline twice daily were followed by a complete recovery. The 2022 monkeypox outbreak in many non-endemic countries almost exclusively affects men who have had sex with other men, and sexual transmission has been strongly postulated since MPX virus (MPXV) was found via qPCR in the semen of MSM.1 The clinical manifestations of the 2022 outbreak may differ from those previously described: Isolated genital and perianal presentations and proctitis are increasingly identified and sometimes make the differential diagnosis with other sexually transmitted diseases difficult.2 The clinical presentation of our patient was atypical because the lesions initially appeared on the hand and glans simultaneously followed by other sites, whereas in the current outbreak lesions are typically described as appearing first on the genitals and then spreading. In our case, we also observed a multiple bacterial superinfection of ulcerated skin lesions caused by monkeypox, along with significant edema, erythema, and pain in the affected areas, resembling cellulitis. Although dermal and subcutaneous infections, such as cellulitis, are not typically associated with MPX, the natural progression of skin lesions with ulceration may create an entry point for bacterial skin infections.3 Seven precedent cases of bacterial superinfection of the skin were identified through a search of the literature. All cases involved men, with a median age of 34 years (IQR: 30–36); of these, four were HIV positive. The cases reported mainly cellulitis of the genitals. The nipple, nose, and inguinal area were also involved. In three cases, fever was reported but wasn't considered directly related to bacterial infection. An elevated value of C-reactive protein was shown in five patients (from 12 to 80 mg/l), and antibiotic therapy was administered to all patients, with hospitalization in six. Complete recovery was observed in all cases. In conclusion, bacterial superinfections may be a significant complication of MPXV infections and can determine hospitalization and more challenging patient management. Superinfections can occur at any stage of the disease and prolong the illness. During the follow-up, clinicians must be vigilant and maintain a high index of suspicion, especially in immunocompromised patients.