A new modification to the Psoriasis Area and Severity Index (PASI) aims to address limitations of the scale when used to assess mild-to-moderate disease. PASI-high discrimination (PASI-HD), designed to be used in clinical trials among patients for whom the areas of affected body surface are less than 10 percent, was developed by Arcutis Biotherapeutics, Inc. in conjunction with leading psoriasis experts.

“The majority of people affected by plaque psoriasis experience mild or moderate disease, yet clinicians lack the best possible tools to provide an accurate measurement of severity for those individuals,” says Robert Higham, MPAS, PA-C, Executive Director of Clinical Development for Arcutis and one of the authors of the article. “As we work toward bringing topical treatment innovations for psoriasis to dermatologists and patients, we believe innovations are likewise needed to improve the tools and methods to properly diagnose and track all levels of disease and treatment effects.”

To determine a PASI score, the area of body region affected by psoriasis is estimated and given a number, but for body areas with less than 10 percent of disease, a non-granular score of 1 is applied regardless of the actual extent of disease, masking any changes in disease extent between 0 and 9 percent.

Details of the new PASI-HD approach appear in Dermatology and Therapy.