Recategorization of psoriasis severity: Delphi consensus from the International Psoriasis Council

Background: Psoriasis severity categories have been important tools for clinicians to use in treatment decisions as well as to determine eligibility criteria for clinical studies. However, owing to the heterogeneity of severity classifications and their lack of consideration for the impact of psoriasis involvement of special areas or past treatment history, patients may be miscategorized, which can lead to undertreatment of psoriasis. Objective: To develop a consensus statement on the classification of psoriasis severity. Methods: A modified Delphi approach was developed by the International Psoriasis Council to define psoriasis severity. Results: After completion of the exercise, 7 severity definitions were preferentially ranked. This most preferred statement rejects the mild, moderate, and severe categories in favor of a dichotomous definition: Psoriasis patients should be classified as either candidates for topical therapy or candidates for systemic therapy; the latter are patients who meet at least one of the following criteria: (1) body surface area >10%, (2) disease involving special areas, and (3) failure of topical therapy. Limitations: This effort might have suffered from a lack of representation by all relevant stakeholders, including patients. Conclusion: The consensus statement describes 2 categories of psoriasis severity, while accounting for special circumstances where patients may require systemic therapy.