Folliculitis decalvans: a multicentre review of 82 patients.

Background: Folliculitis decalvans (FD) is a rare neutrophilic scarring alopecia that represents a therapeutic challenge for dermatologists.

Objective: To describe the epidemiology, comorbidities, clinical presentation, diagnostic findings and therapeutic options in a large series of patients with FD.

Methods: This retrospective multicentre review includes patients diagnosed with FD based on clinical and histopathologic findings. The clinical severity was determined by the maximum diameter of the largest alopecic patch (slight: <2 cm, moderate: 2-4.99 cm, severe: 5 cm or more). Response to therapy was assessed as improvement, worsening or stabilization depending on the clinical symptoms (pruritus and trichodynia), inflammatory signs (erythema, pustules and crusts) and the extension of the alopecic patch.

Results: Overall, 82 patients (52 males and 30 females) with a mean age of 35 years were included. No significant comorbidities were present. A family history was present in three males. Severe FD was observed in 17 patients (21%). The independent factors associated with severe FD after multivariate analysis were: onset of FD before 25 years of age and presence of pustules. Oral antibiotics (tetracyclines and the combination of clindamycin and rifampicin) improved 90% and 100% of the patients, with a mean duration of response of 4.6 and 7.2 months respectively.

Conclusions: The onset of FD before 25 years of age and the presence of pustules within the alopecic patch were associated with severe FD. Tetracyclines and the combination of clindamycin and rifampicin were the most useful treatments.