Risk factors for frontal fibrosing alopecia: A case-control study in a multiracial population

J Am Acad Dermatol. 2021 Mar;84(3):712-718. doi: 10.1016/j.jaad.2020.08.076. Epub 2020 Aug 22.


Background: Frontal fibrosing alopecia (FFA) is a chronic cicatricial alopecia with unknown etiology and a worldwide rising incidence.

Objective: The objective of this study was to evaluate the association of FFA with demographic and exposure factors in a Brazilian multiracial population.

Methods: A multicenter case-control study was conducted in 11 referral centers throughout Brazil. The study was a case-control study that prospectively recruited 902 participants (451 patients with FFA and 451 sex-matched control individuals). Study participants completed a thorough questionnaire comprising variables grouped as baseline demographics, environmental exposure, diet, hormonal factors, allergies, and hair and skin care.

Results: When adjusted by sex, age, menopause, and skin color, FFA was associated with hair straightening with formalin (odds ratio [OR], 3.18), use of ordinary (nondermatologic) facial soap (OR, 2.09) and facial moisturizer (OR, 1.99), thyroid disorders (OR, 1.69), and rosacea (OR, 2.08). Smokers (OR, 0.33) and users of antiresidue/clarifying shampoo (OR, 0.35) presented a negative association with FFA. There was no association with the use of sunscreen.

Limitations: Recall bias.

Conclusions: The association with moisturizers, ordinary facial soap, and hair straightening with formalin and the negative association with antiresidue/clarifying shampoo reinforce the possibility of an exogenous particle triggering FFA.

Keywords: case-control; frontal fibrosing alopecia; risk factors; sunscreens; tobacco.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Alopecia / epidemiology*
  • Alopecia / etiology
  • Alopecia / pathology
  • Brazil / epidemiology
  • Case-Control Studies
  • Cicatrix / epidemiology*
  • Cicatrix / etiology
  • Cicatrix / pathology
  • Female
  • Forehead
  • Formaldehyde / adverse effects
  • Hair Preparations / adverse effects
  • Hair Preparations / chemistry
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Prospective Studies
  • Protective Factors
  • Risk Assessment / statistics & numerical data
  • Risk Factors
  • Rosacea / epidemiology*
  • Skin / pathology
  • Smoking / epidemiology*
  • Soaps / adverse effects
  • Surveys and Questionnaires / statistics & numerical data
  • Thyroid Diseases / epidemiology*


  • Hair Preparations
  • Soaps
  • Formaldehyde