Incidence estimates for lichen planopilaris and frontal fibrosing alopecia in a New York City health care system.

Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are scarring alopecias that cause significant distress and psychological morbidity. Limited studies have been performed examining the epidemiology of FFA and LPP. We performed a retrospective case cohort analysis by querying for patients with the ICD 10 code L66.1 (LPP, FFA) between 2015 and 2018 using the Clinical Data Warehouse (CDW) at NewYork-Presbyterian Hospital and Columbia Doctors. We calculated the one-year incidence of LPP/FFA between January 1, 2018 to December 31, 2018 by identifying all patients without a previously recorded ICD code for L66.1 who presented as a new hair loss patient based on chart review. A total of 170 patients were identified with a new diagnosis of LPP or FFA in 2018 among 1,187,583 patients. The standardized incidence per 100,000 was 12.75 for LPP and FFA combined, 7.35 for LPP alone, and 5.41 for FFA alone. The incidence peaked in the 51 to 60 age range (3.36). The incidence was highest in non-Hispanic White patients (17.27), White patients of unknown ethnicity (26.26), and non-Hispanic Asian patients (17.27). In New York City, LPP and FFA are uncommon diseases that are most common in middle-aged females and non-Hispanic White patients.