Polarization-independent edge detection based on the spin-orbit interaction of light.

INTRODUCTION

Frontal fibrosing alopecia (FFA) has been associated with hair cosmetic habits, yet causality and frequency-dependent effects remain uncertain. This study aimed to evaluate the association between hair care habits and FFA.

METHODS

An analytical case-control study was conducted including 115 FFA patients and 112 matched controls, evaluated at the Hospital Italiano de Buenos Aires between 2015 and 2024. Participants reported current hair washing frequency, cosmetic hair practices, leave-in-product use, and sunscreen use; FFA cases also reported habits 5 years before symptom onset. Logistic regression models were performed.

RESULTS

Decreasing hair washing frequency was associated with progressively higher odds of FFA (adjusted OR 18.7 for washing ≤1 time/week compared with daily washing). In dichotomized models, daily washing remained protective (adjusted OR 0.31; p = 0.012). Cosmetic hair procedures ≥2/year and leave-in product use ≥1/week significantly increased risk (adjusted OR 2.39 and 4.98, respectively). Sunscreen use showed no association with FFA in any model.

CONCLUSION

Frequent cosmetic procedures and leave-in product use were associated with higher odds of FFA, whereas daily washing was protective. These findings underscore the potential contribution of cumulative exposure to cosmetic substances in FFA pathogenesis and highlight modifiable behavioral factors warranting further study.