WEDNESDAY, May 10, 2023 -- Skin lesions were frequently the first sign of mpox infection during the 2022 mpox outbreak, according to a study published in the May issue of the Journal of the American Academy of Dermatology.

Sonya Prasad, from Massachusetts General Hospital in Boston, and colleagues characterized skin lesion morphology, symptomatology, and outcomes of mpox infection over time based on patient cases from the American Academy of Dermatology/International League of Dermatological Societies Dermatology COVID-19, Mpox, and Emerging Infections Registry, maintained by heath care professionals.

Data were entered for 101 cases in 13 countries from Aug. 4 to Nov. 13, 2022, mainly by dermatologists (92 percent). The researchers found that 39 percent of patients had fewer than five lesions. In more than half of cases (54 percent), the first sign of infection was skin lesions. Papules (36 percent), vesicles (17 percent), and pustules (20 percent) predominated in the first one to five days of infection. Pustules were most common (36 percent) by days 6 to 10, followed by erosions/ulcers and crusts/scabs (27 and 24 percent, respectively). After day 11, crusts/scabs were the predominant morphology. There were 10 cases of morbilliform rash. In 13 percent of the cases, scarring occurred.

"These findings reinforce deviations in skin findings in the current mpox outbreak compared to prior mpox outbreaks -- notably the presence of skin lesions prior to the onset of systemic illness and the presence of fewer than 20 skin or mucocutaneous lesions overall," the authors write.