International Psoriasis Council

Advancing Knowledge. Improving Care.

Advancing Knowledge. Improving Care.

Generalized Pustular Psoriasis


Project Description

IPC’s pustular psoriasis working group’s goal is to improve the understanding of this rare and life-threatening disease and conduct activities to improve patient treatment. Preliminary plans for 2022-2023 include: Reaching an international consensus on the classification of pustular psoriasis and related diseases; defining the objectives and addressing the feasibility of real-world data collection through international collaboration with pustular psoriasis clinical centers and laboratories; reaching a global consensus on pustular psoriasis scoring assessments; initiating intra-rater and inter-rater variability validation studies; and developing training modules on pustular scores and certification for clinical trial investigators.

Project Leaders

Siew Eng




Hospital Sultanah Aminah Johor Bahru, School of Medicine and Health Services, Monash University Malaysia


Hervé Bachelez Headshot





Hôpital Saint-Louis, Imagine Institute for Human Genetic Diseases, Paris Cité University


Working Group Members

  • Jonathan Barker, United Kingdom
  • Francesca Capon, United Kingdom
  • Claudia de la Cruz, Chile
  • Johann Gudjonsson, United States
  • Akimichi Morita, Japan
  • Ricardo Romiti, Brazil

Project Results


International Consensus Definition and Diagnostic Criteria for Generalized Pustular Psoriasis from the International Psoriasis Council

International Consensus Definition and Diagnostic Criteria for Generalized Pustular Psoriasis From the International Psoriasis Council. Choon SE, van de Kerkhof P, Gudjonsson JE, et al. JAMA Dermatol. Published online May 01, 2024. doi:10.1001/jamadermatol.2024.0915


Importance: Generalized pustular psoriasis (GPP) lacks internationally accepted definitions and diagnostic criteria, impeding timely diagnosis and treatment and hindering cross-regional clinical and epidemiological study comparisons.

Objective: To develop an international consensus definition and diagnostic criteria for GPP using the modified Delphi method.

Evidence Review: The rarity of GPP presents a challenge in acquiring comprehensive published clinical data necessary for developing standardized definition and criteria. Instead of relying on a literature search, 43 statements that comprehensively addressed the fundamental aspects of the definitions and diagnostic criteria for GPP were formulated based on expert reviews of 64 challenging GPP cases. These statements were presented to a panel of 33 global GPP experts for voting, discussion, and refinements in 2 virtual consensus meetings. Consensus during voting was defined as at least 80% agreement; the definition and diagnostic criteria were accepted by all panelists after voting and in-depth discussion.

Findings: In the first and second modified Delphi round, 30 (91%) and 25 (76%) experts participated. In the initial Delphi round, consensus was achieved for 53% of the statements, leading to the approval of 23 statements that were utilized to develop the proposed definitions and diagnostic criteria for GPP. During the second Delphi round, the final definition established was, “Generalized Pustular Psoriasis is a systemic inflammatory disease characterized by cutaneous erythema and macroscopically visible sterile pustules.” It can occur with or without systemic symptoms, other psoriasis types, and laboratory abnormalities. GPP may manifest as an acute form with widespread pustules or a subacute variant with an annular phenotype. The identified essential criterion was, “Macroscopically visible sterile pustules on erythematous base and not restricted to the acral region or within psoriatic plaques.”

Conclusions and Relevance: The achievement of international consensus on the definition and diagnostic criteria for GPP underscores the importance of collaboration, innovative methodology, and expert engagement to address rare diseases. Although further validation is needed, these criteria can serve as a reference point for clinicians, researchers, and patients, which may contribute to more accurate diagnosis and improved management of GPP.

Link to article


This PowerPoint PDF slide summarizes the content of the IPC publication ‘International Consensus Definition and Diagnostic Criteria for Generalized Pustular Psoriasis.’ It encapsulates the consensus process involving 33 global experts, key findings, impact, and future directions outlined in the publication. It aims to enhance understanding and standardization in diagnosing and managing Generalized Pustular Psoriasis.

This PowerPoint PDF slide focuses on the achieved consensus definition and key diagnostic criteria for GPP in the IPC publication ‘International Consensus Definition and Diagnostic Criteria for Generalized Pustular Psoriasis,’ offering a standardized framework to enhance clinical practices and global research comparability.

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