Prurigo nodularis (PN) is a chronic skin condition that affects an estimated 72 out of 100,000 people in the United States. Black patients and other minority groups are disproportionately affected by the disease. Patients with PN have extremely itchy nodules on their arms and legs, which severely affect their quality of life.

Johns Hopkins researchers identified two different groups of patients with PN: those who had increased inflammation in the blood and those who didn’t but were more likely to have a history of spinal disease that can sensitize the nerves. Identifying people with unique types of inflammation can help clinicians provide more accurate and personalized treatment for the condition.

In a study published October 27 in the Journal of Investigative Dermatology, Shawn Kwatra, MD, an assistant professor of dermatology at the Johns Hopkins University School of Medicine, and colleagues found that there are patients with different inflammation profiles in their bodies .

We have seen thicker, more fibrotic nodules in black patients with PN, so we hypothesized that there would be a unique inflammatory signature in the blood. We have also found that some patients respond very well to immunomodulatory therapies while others do not.

Shawn Kwatra, MD, Assistant Professor of Dermatology, Johns Hopkins University School of Medicine

Using algorithms on a wide range of patient blood values, Kwatra and his colleagues were able to characterize different patterns of cytokines – small proteins in the blood that regulate inflammation in the body and control the immune system.

They found two different clusters: non-inflammatory plasma profiles, in which the patients were more likely to develop spinal disease (cluster 1) and inflammatory plasma profiles (cluster 2). Cluster 1 included fewer patients from a minority who had a higher rate of myelopathy (an injury to the spinal cord due to severe compression). Cluster 2 included more black patients with more itching.

By identifying these clusters, clinicians can better understand how to select appropriate treatments that are personalized for PN patients on drugs that primarily treat inflammation versus drugs that treat myelopathy.

“We know that therapy cannot be a one-size-fits-all approach,” says Kwatra. “The goal is to understand the specifics of each patient so that we can tailor treatment with precision medicine. These data show why this is so important. “

Kwatra hopes to study a larger cohort of patients next in order to gather more information and build on that research.


Journal reference:

Sutaria, N., et al. (2021) Cluster analysis of circulating plasma biomarkers in prurigo nodularis shows a pronounced systemic inflammatory signature in African Americans. Journal of Investigative Dermatology.


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