Unique skin symptoms of the current monkeypox outbreak include pseudo-pustules

A review of 185 cases of monkeypox – published in the British Journal of Dermatology – has found that the main features of the current outbreak differ from past cases.

Pivotally, the research found that the main symptom is not pustules, as previously described, but much rarer ‘pseudo-pustules’.

The research, conducted by a network of Spanish dermatologists, categorised key features of the current monkeypox outbreak. The 185 cases studied represent 9% of those reported to the Spanish national surveillance system by 11 July 2022.

While fever and lymph node swelling remained common in this current outbreak, the research found that cases tended to feature few skin lesions, sometimes appearing only in a single area with most starting on the genitals, face, arms, hands and perianal area.

Previous research into the outbreak had described these lesions as pustules, however, it has emerged that these are actually pseudo-pustules. These are similar in appearance to pustules, but are actually whitish, raised lesions. With ‘real’ pustules it is possible to scrape away the top layer of the lesions but with pseudo-pustules it is not possible.

Other skin symptoms include ulcers where the pseudo-pustules meet the moist, inner linings of body cavities such as the nose, mouth, or genital areas, also known as mucous membranes. These mucosal ulcers can be the most common lesions in certain cases.

The researchers also found that well-controlled human immunodeficiency virus (HIV) did not seem to affect the severity of the disease.

Dr Ignacio García Doval, coordinator of the research from the Spanish Academy of Dermatology, explained: “A crucial aspect of managing a fast-moving disease outbreak is having as much information as possible. Our research shows that the symptoms of the current outbreak are unusual and there is evidence that this is due to skin-to-skin contact during sex. Rather than the typical widespread rash seen in past cases, recent cases tend to have far fewer skin lesions, often in one location.”

“No patient involved in this research died and hospitalisation was uncommon, however, the disease is very uncomfortable and can have long-term consequences, including scarring in visible areas,” he added.