Evaluation of the Environmental Risk Factors and Comorbidities in Patients with Lichen Planopilaris: A Case-Control Study.

Introduction: Lichen planopilaris (LPP) is an uncommon cicatricial alopecia clinically characterized by follicular hyperkeratosis, perifollicular erythema, and permanent hair loss. The association of LPP with certain underlying diseases and environmental factors has been evaluated but there are limited data about this association. This study was designated to evaluate the environmental risk factors and comorbidities in LPP patients.

Method: This case-control study was performed on LPP patients referred to two dermatology referral centers from 2019 to 2022. A group of non-LPP healthy individuals referring for cosmetic concerns was recruited as control group. Data collection was performed using two questionnaires: a general questionnaire, including demographic information, comorbidities, environmental risk factors, and disease-related information, and the lichen planopilaris activity index (LPPAI) questionnaire.

Results: One hundred LPP patients as case group were compared with 100 healthy people without LPP as control group. Unemployment, history of major stressful events, thyroid disorder, history of hair dyeing, using face soaps, taking supplements, postmenopausal status, and family history of LPP or other types of alopecia had significant relationship with LPP (all p values <0.05).

Conclusion: LPP has associations with environmental and non-environmental risk factors and, also, genetic component.