Activity-based therapeutic algorithm for folliculitis decalvans: A practical tool for effective management

Abstract

The recent study published in this journal, ‘Management of folliculitis decalvans: The EADV task force on hair diseases position statement’¹ provides practical guidance for diagnosing and managing folliculitis decalvans (FD).

FD is the most common form of primary neutrophilic scarring alopecia typically affecting the scalp (most often the vertex), but also other hair-bearing areas (beard, neck, axillae and pubic region). It has a chronic-relapsing course and is associated with increased cardiovascular risk.² Therefore, accurate diagnosis and management are crucial to control scalp inflammation, prevent irreversible scarring and avoid systemic complications due to persistent inflammation.

Clinical diagnosis of FD is usually straightforward, but overlaps with lichen planopilaris (LPP) are not uncommon, both clinically and pathologically. This has been recently described as FD-LPP phenotypic spectrum (FDLPPPS), considered a progression from acute neutrophilic to chronic lympho-plasmocytic inflammation. Interestingly, Staphylococcus aureus levels differ between these patterns: higher than 20% in FD, but lower in FDLPPPS.³

Hair experts from this task force emphasize the importance of trichoscopy for diagnosis, assessing disease activity and selecting optimal biopsy sites.

By integrating a comprehensive literature review with expert insights, this study introduces a therapeutic algorithm that significantly advances therapeutic decision-making. The algorithm is tailored to disease activity, assessed using the Investigator's Global Assessment score of FD activity (FD-IGA) and the Trichoscopy Activity Scale for FD. These scoring systems, respectively, evaluate clinical and trichoscopic features of peri- and interfollicular erythema, follicular pustules and crusts, among others.

This comprehensive approach is useful for dermatologists managing a disease where clinical trials and head-to-head studies comparing treatments are lacking, with all medications being off-label.

The therapeutic strategy divides management into two phases: the acute inflammatory phase, marked by pustules and exudative crusts, and the mild inflammatory phase, which may follow the treatment of the previous active phase or present mildly from the onset. Anti-inflammatory therapy in the acute phase includes oral antibiotics, alone or combined with oral corticosteroids for highly active disease.

Oral antibiotics are recommended for their activity against S. aureus, a key contributor to FD pathogenesis and for their immune modulating and anti-inflammatory functions. Tetracyclines administered for 3 months, or a 10-day combination therapy of clindamycin and rifampicin, are commonly prescribed. However, while the latter is believed to reduce relapse rates, recent studies and our experience do not confirm this.⁴ Moreover, we believe that antibiotics essential for systemic infections should be avoided due to the potential risk of antibiotic resistance.

Mild FD activity is characterized by perifollicular erythema and scales without follicular pustules and crusts. In the task force algorithm, the management of this phase prioritizes oral isotretinoin as first-line therapy. Isotretinoin was studied as monotherapy in a retrospective analysis of 39 male patients, 89.7% presenting with pustules.⁵ Other isotretinoin studies lack detailed clinical and trichoscopic descriptions, leaving uncertainty about whether it was used during the active inflammatory phase or as maintenance therapy, potentially within FDLPPPS.

The algorithm includes additional therapies, both systemic and topical. Among oral antibiotics, macrolides and trimethoprim-sulfamethoxazole have been used, the latter more commonly in regions with high tuberculosis prevalence. Other second-line therapies include dapsone, cyclosporine, hydroxychloroquine, TNF-alpha inhibitors (adalimumab), JAK inhibitors (baricitinib, tofacitinib) and photodynamic therapy. Surgical interventions such as excision, Nd: YAG laser therapy, and hair transplantation may also be considered in selected cases.

As adjuvant therapy, first-line treatments include topical or intralesional steroids and topical antibiotics. Second-line options consist of topical tacrolimus 0.1% or topical dapsone 5%.

Offering a schematic guideline based on objective clinical and trichoscopic features, this study represents a very important step for future research assessing new treatment strategies for FD.

AB: none; AT: DS Laboratories, Almirall, Tirthy Madison, Eli Lilly, Pfizer, Myovant, Bristol Myers Squibb, Ortho Dermatologics, Sun Pharmaceuticals, Abbvie, WellBeauty Company LLC, L'Oreal/Vichy USA, Amgen LLC.