Introduction: We sought to understand key symptoms of generalized pustular psoriasis (GPP) and to confirm the relevance to patients and content validity of the Psoriasis Symptom Scale (PSS) in GPP.
Methods: A targeted literature review and clinical expert interviews were conducted as background research. Patients were interviewed individually (involving concept elicitation and cognitive interviews), and a separate patient workshop was conducted to determine disease-specific symptoms of importance.
Results: Seven participants with moderate (n = 4), severe (n = 2), and mild (n = 1) GPP and clinician diagnosis were interviewed. During concept elicitation, all participants indicated that pustules may underlie other symptoms. Symptoms reported by all patients were pain, redness, itch, burning, and discomfort. The PSS symptoms of pain, itching, burning, and redness were reported by ≥ 86% of patients as most frequently experienced. Upon debriefing, the PSS was well understood. Relevance and importance of these symptoms was confirmed in the GPP patient workshop.
Conclusion: Participant feedback found the PSS measure to be relevant and easy to understand. The symptoms included in the instrument, pain, redness, itch, and burning, were most frequently reported, important, and well understood by patients. Study results provided support for the content validity of the PSS for use as endpoints in GPP clinical trials.
Keywords: Generalized pustular psoriasis; Patient-reported outcome; Psoriasis Symptom Scale.
Generalized pustular psoriasis (GPP) is a severe rare disease, including redness and boils that sometimes come with fever and other general symptoms. This study asked patients with GPP about their key symptoms, and whether the Psoriasis Symptom Scale (PSS) is relevant to them as patients. The PSS is a questionnaire with the symptoms pain, itching, burning, and redness. We searched the literature and interviewed clinical experts to guide the patient interviews. Patients were recruited through clinical sites and the National Psoriasis Foundation (NPF). The interviews discussed GPP symptoms and the PSS questionnaire. Patients with GPP were also asked about commonly experienced symptoms in a workshop. Most patients had moderate to severe GPP. Patients in both the interviews and workshop described experiencing pain, redness, itch, burning, and discomfort with their boils. During interviews, the patients said the PSS questionnaire was easy to understand. Patients in the workshop also found the PSS to be relevant and easy to understand. Patients agreed the symptoms in the PSS, pain, redness, itch, and burning, were common and important. Study results support the PSS for use with patients in clinical trials.
© 2022. The Author(s).