Supplementary Material for: Illness Perceptions, knowledge, and Quality of Life in Lichen Planopilaris patients

Introduction Lichen planopilaris (LPP) is an inflammatory disease, leading to permanent hair loss, which significantly affects the psychosocial and self-image of patients with this condition; however, the impact of this condition on patients’ quality of life (QoL), their perception of disease, and their knowledge have rarely been studied. This study aimed to investigate patients' knowledge and perspective on their disease and its association with their QoL and the extent of skin involvement. Methods Patients with confirmed LPP from 2022 to 2023 completed a questionnaire covering demographic characteristics, the Illness Perception Questionnaire, disease and therapy knowledge, and the Dermatology Life Quality Index. Additionally, a dermatologist examined the Lichen Planopilaris Activity Index (LPPAI). Results This study enrolled 42 LPP patients, with 81% being female and 73.8% under 60 years old. The LPPAI did not correlate with knowledge (r =0.04, p = 0.783), illness perception (r = 0.097, p = 0.543), or QoL scores (r = 0.119, p = 0.452). However, QoL was positively linked to knowledge (r = 0.382, p = 0.013) and illness perception scores (r = 0.398, p = 0.009). Patients with a longer disease duration had higher knowledge scores (r = 0.400, p = 0.009). Conclusion Dermatologists should educate patients about their condition and understand their perceptions to improve treatment outcomes and quality of life.