Biologics in Folliculitis Decalvans : an Adaptative Trial Research

Overview

FD (which was in the past named Quinquaud folliculitis) is a rare disease defined by a chronic, neutrophilic folliculitis of the scalp, leading to scarring alopecia. During the flares, scabs and pustules, sometimes very extensive and painful, induce definitive alopecia with quality of life is considerably impaired. Pathophysiology remains unclear although the cutaneous microbiota with a rupture of the epidermal barrier, leading to pathogen invasion, most often Staphylococcus aureus (SA), has been involved.It explains why first-line treatment of FD is antibiotics, i.e., oral tetracycline/doxycycline (combined with topical antibiotics) for 3 months at least. Second-line treatment includes an association of antibiotics, e.g., rifampicin-clindamycin for 10-12 weeks or, in case of contraindication or unavaibility of one or both of these drugs, other antibiotics listed. Short-term efficacy rate of antibiotics is around 50-60%, but unfortunately, recurrences/relapses are occurring 5 to 7 months on average after stopping antibiotics, requiring their reintroduction/long-term use and potentially less efficacy/ecological harms. So far, FD is a non-curable disease for which inflammatory pathways involving several cytokines as TNF, IL1β, IL8, TGFβ, IL12 and 23, could also play a role.

Folliculitis Decalvans (FD) is a rare disease defined by a chronic, neutrophilic folliculitis of the scalp, leading to scarring alopecia. During the flares, scabs and pustules, sometimes very extensive and painful, induce the definitive alopecia. As expected, quality of life is heavily impaired. Pathophysiology remains unclear although the microbiota with a rupture of the epidermal barrier, leading to pathogen invasion, most often Staphylococcus aureus (SA), has been involved. It explains why first-line treatment of FD is antibiotics, i.e., oral tetracycline / doxycycline (combined with topical antibiotics) for 3 months at least. Second-line treatment includes an association of antibiotics, e.g., rifampicin-clindamycin for 10-12 weeks. Short-term efficacy level of antibiotics is around 50-60% but unfortunately, recurrences/relapses are occurring 5 to 7 months after stopping antibiotics on average, requiring their reintroduction/long-term use and potentially less efficacy. So far, FD is a non-curable disease for which inflammatory pathways involving several cytokines as TNF, IL1β, IL8, TGFβ, IL12, IL 23, could also play a role. The similarity of FD with hidradenitis suppurativa (HS) suggests a double approach based on antibiotics and immunomodulatory targeted drugs. Only short series have been reported in attempting to control the inflammatory response by biologic agents, including anti-TNF, anti-IL12 and IL23, JAK inhibitors. Although several cures of antibiotics could be delivered lifelong, it may impair the microbiota at the individual and populational levels with known (and possibly still unknown) ecological consequences. With regards to limited available treatment, potential harms of antibiotics, and absence of therapeutic strategy, any new treatment able to control signs and symptoms of flare of FD in patients previously treated by 2 lines of antibiotics - so called difficult-to- treat patients - could be used in a forthcoming strategy. We hypothesized that targeted therapies as biologics could control a flare of FD in difficult-to-treat patients with a relevant response. With regards to the literature, this approach would allow a new clue in the management of FD.