Redefining Special Cases of Psoriasis Severity

Current categories of classifying psoriasis, such as mild, moderate, or severe, do not consider past treatments or involvement of special areas, leading to undertreatment, a report said.

The International Psoriasis Council (IPC) created a consensus statement to define 2 categories of psoriasis severity that account for special circumstances where patients may require systemic therapy.

According to the recent report, published by the Journal of the American Academy of Dermatology, psoriasis severity categories are used by clinicians to help determine treatment decisions and eligibility for clinical studies. However, the current categories, such as mild, moderate, or severe, do not consider past treatments or involvement of special areas, leading to undertreatment.

“There is no consensus regarding the definition for patients affected by lower levels of BSA [body surface area] involvement who, nonetheless, have disease characteristics that may severely impact quality of life and disability,” explained the authors. “Typically, only patients with a minimum of 10% BSA are permitted entry to clinical trials of newer targeted agents, so evidence is lacking about the efficacy of these agents in patients with lower BSA involvement or disease involving special sites. This also impacts the approval of agents for patients with lower degrees of skin involvement, with some national health systems and third-party payers declining reimbursements for patients who do not have at least 10% BSA involvement.”

Using a modified Delphi approach, researchers conducted a brainstorming stage, 2 rounds of voting, and held a consensus meeting in order to develop a consensus statement for classifying psoriasis severity. Seventy-eight anonymous statements were collected from IPC board members and others as well as from corporate sponsors.

Following 2 rounds of voting and consideration for 30 statements, the 7 statements with the highest scores were chose for voting in round 3 at an in-person consensus meeting. Each statement was presented and discussed and the participants voted anonymously in order to arrive at a final ranking of the statements.

The final consensus statement that received the highest score said patients with psoriasis "should be classified as candidates for topical therapy or candidates for systemic therapy. The latter are patients who meet at least 1 of the following criteria: BSA >10%, disease involving special areas, or failure of topical therapy."

The authors explained that this Delphi exercise represents an international consensus for the classification of psoriasis severity that can be used in both clinical and research settings.


Strober B, Ryan C, van de Kerkhof P, et al. Recategorization of psoriasis severity: Delphi consensus from the International Psoriasis Council [published online August 16, 2019]. J Am Acad Dermatol. doi: 10.1016/j.jaad.2019.08.026.