Understanding a New Method of Assessing Psoriasis Severity

There are a multitude of biologics for the treatment of psoriasis—in fact, 11 FDA-approved biologics for the treatment of moderate to severe psoriasis. These treatments now help psoriasis patients achieve clearer skin along with better safety. However, only approximately up to 20 percent of patients who have moderate to severe psoriasis are treated with systemic therapy. To help patients get access to the proper treatments for their disease level, the International Psoriasis Council (IPC) of more than 100 physician leaders in dermatology from around the world is proposing a new method to classify psoriasis severity to guide providers on where to start treatment.¹

Instead of the mild, moderate, and severe labels that traditionally have been used to determine psoriasis severity or psoriasis body surface area >10%, the group’s consensus statement proposes a treatment-focused approach that classifies patients as candidates for either topical therapy or systemic therapy. The goal is to simplify the process of getting psoriasis patients on the right medication.

The IPC Classification

In both clinical practice and clinical trials currently, there are several methods in use to determine psoriasis severity. Many methods focus on the percentage of body surface area with psoriasis lesions and then categorize patients as mild, moderate, or severe. The Psoriasis Area Severity Index (PASI) is another measure that quantifies the extent of the psoriasis lesions as well as individual characteristics of the plaques—erythema, induration, and scale. But none of these approaches takes into account the impact of psoriasis on quality of life, past treatment history, or psoriasis in sensitive areas of the body, such as face, nails, hands/feet, and genitals. As a result, miscategorization of patients can lead to under-treatment of psoriasis and impact the approval of systemic medications by insurance.

The IPC used a systematic multistep process to reach consensus. This process allowed for debate of the different severity measures, which included an acknowledgment of the high variability across countries and regions. The group ultimately agreed that severity definitions need to reflect the extent of involvement as well as the importance of lesion location and its impact on quality of life and function.

The IPC proposes two categories to measure psoriasis severity:

1. Candidates for topical therapy

2. Candidates for systemic* therapy meet one of the following criteria:

a. BSA>10%

b. Disease involving special areas (face, palms, soles, scalp or nails)

c. Failure of topical therapy

*Systemic therapy: biologic and nonbiologic treatments including phototherapy and oral systemic treatments.

This new classification of psoriasis severity is part of the IPC’s goal to increase access to care for patients and improve the health of psoriasis patients around the world. Patients who show less involvement than PASI 10 or BSA 10 were not eligible for biologics and could be denied access to these medications in many countries, even though those patients may have significant disability. The IPC also intends to work with health insurance systems and providers as well as clinical trials to integrate this new method of assessing psoriasis severity into standards of care for psoriasis.

Patient Preference Counts, Too

In combination with the IPC’s initial approach to disease assessment, the patient’s wishes and preferences should be taken into consideration. One study showed that patient expectations did not align with those of the clinician almost a third of the time. Discordance between the provider and patient expectations is a consequence of poor communication, which often leads to undertreatment.² Clinicians may rely on objective measures (BSA, PASI) and forget to take into consideration the patients’ expectations about the treatment outcomes.

Clinicians need to be upfront in asking patients how psoriasis impacts their daily life, including asking about symptoms of depression and anxiety. My personal approach is to ask patients directly, “How does psoriasis affect your daily life? What about your psoriasis bothers you the most? What are your treatment goals?”

Patient expectations often relate directly to personal goals but also include a broad range of considerations of medication safety and skin clearance. Some personal goals include: better interpersonal relationships, enjoyment of physical intimacy, less psychological discomfort about the disease, or simply to stop itching.

Putting it Together

As the number of effective therapies for psoriasis continues to rise, optimizing treatment requires careful consideration of disease severity along with drug characteristics and patient preferences. Providers should consider patient goals and incorporate them into disease management.

1. Strober B, et al. “Re-Categorization of Psoriasis Severity: Delphi Consensus from the International Psoriasis Council.” In press. https://www.jaad.org/article/S0190-9622(19)32573-3/pdf

2.Armstrong AW, Robertson AD, Wu J, Schupp C, Lebwohl MG. “Undertreatment, Treatment Trends, and Treatment Dissatisfaction Among Patients With Psoriasis and Psoriatic Arthritis in the United States: Findings From the National Psoriasis Foundation Surveys, 2003-2011.” JAMA Dermatol. 2013;149(10):1180–1185. doi:10.1001/jamadermatol.2013.5264