International Psoriasis Council

International Psoriasis Council
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Advancing Knowledge. Improving Care.

Recategorization of Psoriasis Severity

IMPROVING THE CLASSIFICATION OF PSORIASIS SEVERITY

Project Description

The current clinical definitions of psoriasis severity are narrowly defined and overlook the unique challenges faced by each patient, which may include localized lesions in specific areas and/or comorbidities. A more specific clinical severity classification is needed and would guide clinical decision-making to be more practical, meaningful, and better aligned with the true severity of a patient’s disease; strengthen psoriasis treatment guidelines and guide future clinical trials of drugs targeting various severities of psoriasis.

In Phase I of the project, the Delphi method was used to come to consensus, among IPC’s network of key opinion leaders, on a definition for each category of disease severity. As the result of the reclassification Delphi, IPC recommends that patients be considered a candidate for topical-only therapy or a candidate for systemic therapy.

Patients that meet one or more of the following criteria are candidates for systemic therapy:

  • Psoriasis lesions on 10% or more of body surface; OR
  • Psoriasis lesions on high-impact sites (i.e., hands/feet, face, genitals, scalp); OR
  • Topical therapy failed to control symptoms: inability to achieve clear/nearly clear skin (BSA ≤1%, PGA 0 or 1) after two consecutive 4-week topical therapy courses, per guidelines. Strong consideration should be given when a patient self-reports moderate or severe psoriasis, despite a provider’s mild assessment, and experiences significant physical, psychological, or social impact. 

In Phase II of the project, the working group is focusing on implementing studies that quantify the statement in real-world practice.  In addition, significant work is being done to educate clinicians and patients on the new classification. Future work in Phase II will focus on educating regulatory bodies and developing additional activities to educate clinicians and patients.

Project Leaders

Lone

Skov

,

MD, PhD

Herlev and Gentofte Hospital, University of Copenhagen

Hellerup

,

Denmark

Co-chair

IPC Board Member
Bio

Tiago

Torres

,

MD, PhD

Centro Hospitalar Universitário de Santo António, University of Porto

Porto

,

Portugal

IPC Councilor
Bio

Working Group Members

  • Pravit Asawanonda, Thailand
  • Álvaro González-Cantero, Spain
  • Rudi Chandra, Indonesia
  • Mona El-Kalioby, Egypt
  • Cesar González, Colombia
  • Benjamin Hidalgo Matlock, Costa Rica
  • Julia-Tatjana Maul, Switzerland
  • Filip Rob, Czech Republic

Project Results

ESTABLISHING CONSENSUS ON DEFINING FAILURE OF TOPICAL THERAPY IN PSORIASIS: RECOMMENDATIONS FROM THE INTERNATIONAL PSORIASIS COUNCIL

Strober B, Blauvelt A, van de Kerkhof P, et al. J Am Acad Dermatol. 2025. doi:10.1016/j.jaad.2025.08.116
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SUMMARY

This publication presents expert consensus from the International Psoriasis Council (IPC) on defining failure of topical therapy in psoriasis. Recognizing the global undertreatment of psoriasis and the lack of clarity in national guidelines, the IPC’s Disease Severity Working Group proposes standardized criteria for topical treatment failure. These include the inability to achieve clear or nearly clear skin (≤1% body surface area and Physician’s Global Assessment of 0 or 1) after two consecutive 4-week courses of topical therapy. The guidance emphasizes the importance of patient-reported outcomes, quality of life impact, and the need for timely escalation to systemic therapy or phototherapy when topicals are ineffective. Building on the IPC’s existing disease severity reclassification, this definition further specifies the third criterion for determining candidacy for systemic treatment, providing clinicians with a clear, practical framework to guide treatment decisions and improve patient outcomes worldwide.

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INTERNATIONAL PSORIASIS COUNCIL PSORIASIS DISEASE SEVERITY RECLASSIFICATION: UPDATE ON VALIDITY, ACCEPTANCE, AND IMPLEMENTATION

Strober B, Blauvelt A, van de Kerkhof P, et al. J Am Acad Dermatol. 2025;93(4):1154–1157. doi:10.1016/j.jaad.2025.05.1445
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SUMMARY

This publication provides an update on the global acceptance and real-world application of the International Psoriasis Council’s (IPC) reclassification of psoriasis severity. The IPC framework divides patients into candidates for either topical or systemic therapy based on three criteria: involvement of high-impact sites, body surface area (BSA) >10%, or failure of topical treatment. Emerging evidence from global surveys and registries confirms that patients with low BSA but high-impact site involvement experience significant disease burden, often warranting systemic therapy. The IPC criteria are increasingly reflected in clinical trial designs, national guidelines, and treatment recommendations across multiple countries. This shift promotes more accurate classification, better treatment decisions, and improved patient outcomes by prioritizing disease impact over traditional severity metrics.

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PSORIASIS INVOLVING SPECIAL AREAS IS ASSOCIATED WITH WORSE QUALITY OF LIFE, DEPRESSION, AND LIMITATIONS IN THE ABILITY TO PARTICIPATE IN SOCIAL ROLES AND ACTIVITIES

Blauvelt A, Gondo G, Bell S, et al. Journal of Psoriasis and Psoriatic Arthritis. 2023;8(3):100-106. doi:10.1177/24755303231160683.
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ABSTRACT

Background
Psoriasis severity has traditionally been categorized as mild, moderate, and severe. Commonly, cut-offs for severe disease require a body surface area (BSA) involvement of ≥10% or a Psoriasis Area Severity Index (PASI) > 10. However, clinical experience challenges these traditional measures and requirements, as patients with less extensive psoriasis may have disease that severely impacts quality of life. 

Objective
The objective of the present study was to further explore the extent of patient burden when psoriasis affects special locations.

Methods
A total of 69,190 individuals living in the U.S were invited to participate in a patient advocacy survey by telephone and or web interviews over the course of 3 years (2019-2021). The survey instrument consisted of validated patient-reported outcome measures, measuring disease-specific quality of life (Dermatology Life Quality Index, DLQI), depression (Patient Health Questionnaire (PHQ)-2 and (PHQ)-9), and the ability to participate in social roles and activities (PROMIS Ability to Participate in Social Roles and Activities (SF-4a). Chi-square tests were performed to explore association between psoriasis involvement on special locations and patient outcomes and multivariate logistic regression models were then constructed, to assess impact of having psoriasis on special locations patient outcomes, controlling for potential confounding factors.  

Results
A total of 4129 individuals completed the survey. 3594 (84.4%) of patients surveyed reported psoriasis involving special areas of the bodysuch as the scalp, face, hands, feet, or genitalia. Involvement of special areas is associated with worse quality of life and depression. 35-71% of patients with 10% or less total BSA involvement experienced a moderate-to-extremely large effect on these life function domains. When adjusting for age, sex, and body surface area, psoriasis involvement of a special location was associated with poorer patient reported outcomes. including a 46% less likelihood of reporting their skin disease ass having “no or only a small effect on QoL,” a 30% less likelihood of having a “normal l ability to participate in social roles and activities,” and a 126% higher likelihood of f having depression. Conclusion: Real-world data presented here demonstrate that psoriasis involving special areas is associated with adverse life consequences, including poor quality of life and depression.

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PSORIASIS SEVERITY: COMMONLY USED CLINICAL THRESHOLDS MAY NOT ADEQUATELY CONVEY PATIENT IMPACT

Golbari NM, van der Walt JM, Blauvelt A, Ryan C, van de Kerkhof P, Kimball AB. J Eur Acad Dermatol Venereol. 2020 Sep 25. doi: 10.1111/jdv.16966.
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ABSTRACT

Background
Psoriasis severity is usually evaluated using quantitative and qualitative measures, including percent body surface area (BSA) involvement, the Psoriasis Area and Severity Index (PASI), and the Dermatology Life Quality Index (DLQI), a patient -reported questionnaire. However, standardized definitions for psoriasis severity categories have not been well established. A PASI of 10 or 12 has remained the minimal severity threshold defining eligibility for psoriasis treatments. In the present study, the validity of this cut-off was re-evaluated in the context of quality of life.

Objective
To determine if the thresholds commonly used to define moderate psoriasis (PASI of 10-12 and BSA of 10) are supported by patient-reported DLQ I data. 

Methods
A systematic review of randomized controlled trials that enrolled mild or moderate patients published between January 2000 – June 2017 was used to assess correlations between provider and patient-generated severity at baseline. 

Results
For subject groups with high impact on quality of life (DLQI >10), the mean weighted BSA was 7.6 (Range: 7.1 -8.4) and the mean weighted DLQI was 11 (Range: 10.2 – 12.2). Similarly, the mean weighted PASI for patients with DLQI >10 was 8.7 (Range: 7.1 – 10.1) and the mean weighted DLQI was 10.9 (Range: 10.1 -12.2). Conclusion: Patients with PASI or BSA scores less than 10 can have major quality of life impairment. In general, the objective measures of BSA and PASI alone, when excluding DLQI, may not fully capture the impact of disease severity.

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RECATEGORIZATION OF PSORIASIS SEVERITY: DELPHI CONSENSUS FROM THE INTERNATIONAL PSORIASIS COUNCIL 

Strober B, Ryan C, van de Kerkhof P, van der Walt J, Kimball AB, Barker J, Blauvelt A. Journal of the American Academy of Dermatology (2019), doi: https://doi.org/10.1016/ j.jaad.2019.08.026.
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ABSTRACT

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.

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View more resources on utilizing this new categorization in your clinic.

ABSTRACT

Background

Psoriasis severity is usually evaluated using quantitative and qualitative measures, including percent body surface area (BSA) involvement, the Psoriasis Area and Severity Index (PASI), and the Dermatology Life Quality Index (DLQI), a patient -reported questionnaire. However, standardized definitions for psoriasis severity categories have not been well established. A PASI of 10 or 12 has remained the minimal severity threshold defining eligibility for psoriasis treatments. In the present study, the validity of this cut-off was re-evaluated in the context of quality of life.
 
Objective
To determine if the thresholds commonly used to define moderate psoriasis (PASI of 10-12 and BSA of 10) are supported by patient-reported DLQ I data. 
 
Methods
A systematic review of randomized controlled trials that enrolled mild or moderate patients published between January 2000 – June 2017 was used to assess correlations between provider and patient-generated severity at baseline. 
 
Results
For subject groups with high impact on quality of life (DLQI >10), the mean weighted BSA was 7.6 (Range: 7.1 -8.4) and the mean weighted DLQI was 11 (Range: 10.2 – 12.2). Similarly, the mean weighted PASI for patients with DLQI >10 was 8.7 (Range: 7.1 – 10.1) and the mean weighted DLQI was 10.9 (Range: 10.1 -12.2). Conclusion: Patients with PASI or BSA scores less than 10 can have major quality of life impairment. In general, the objective measures of BSA and PASI alone, when excluding DLQI, may not fully capture the impact of disease severity.

Link to PubMed

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