Risk factors associated with frontal fibrosing alopecia: a multicentre case-control study.

Background: Frontal fibrosing alopecia (FFA) is a chronic cicatricial alopecia with an increasing incidence and unknown aetiology.

Aim: To identify possible environmental and hormonal factors related to FFA.

Methods: We conducted a multicentre case-control study paired by sex and age, and recruited 664 women (335 cases and 329 controls) and 106 men (20 cases and 86 controls). Study subjects completed an exhaustive questionnaire enquiring about pharmacological, environmental, hormonal, social, job exposure, lifestyle, drugs and diet factors to which they were exposed at least 5 years prior to the onset of the disease.

Results: For women, there was a statistical association between alopecia and history of pregnancy (OR = 1.6; 95% CI 1.06-2.41), use of facial sunscreen (OR = 1.6; 95% CI 1.06-2.41) and hormone replacement therapy (HRT) (OR = 1.76; 95% CI 1.11-2.8) or raloxifene (no controls exposed therefore OR was not calculated), exposure to alkylphenolic compounds (OR = 1.48; 95% CI 1.05-2.08), and presence of rosacea (OR = 1.91; 95% CI 1.07-3.39), lichen planus pigmentosus (LPP) (OR = 5.14; 95% CI 1.11-23.6) or hypothyroidism (OR = 1.73; 95% CI 1.11-2.69). For men, there was a statistical association between alopecia and use of facial sunscreens (OR = 11.6; 95% CI 1.7-80.9) or antiageing creams (OR = 1.84; 95% CI 1.04-3.23).

Conclusions: FFA seems to be associated with hormonal exposure (pregnancy, HRT and raloxifene), comorbidities (hypothyroidism, LPP and rosacea) and environmental factors (facial sunscreens, antiageing creams and occupational exposure). Further research is required to analyse the exact mechanism in which these environmental factors participate in the development of this alopecia.