“Folliculitis Decalvans and Lichen Planopilaris” Phenotypic Spectrum: Report of Three Cases

Introduction: folliculitis decalvans (FD) and lichen planopilaris (LPP) are two primary cicatricial alopecias (neutrophilic and "lymphocytic," respectively) recently associated in a phenotypic spectrum. The "folliculitis decalvans and lichen planopilaris" phenotypic spectrum FDLPPPS is a combination of the clinical and histological features of FD and LPP. Our study aims to analyze three cases of a specific disease to better understand its clinical characteristics, evolution, and treatment.

Materials and Methods: We reported 3 cases of FDLPPPS with clinical manifestations, trichoscopy, histopathological features, treatments, and follow-up findings as a new presentation of this spectrum.

Results: We reported 3 cases; two females, and one male, with an average age of 33 years (ranging from 20 to 42 years). The average duration of disease evolution before diagnosis was 6.3 years (ranging from 1 to 10 years). Clinically, they presented with one or multiple alopecic patches on the vertex with pustules and crusts and a receding frontal hairline in one patient. Dermoscopy revealed signs consistent with lichen planopilaris and folliculitis decalvans. A diagnosis of phenotypic spectrum was established through histology. Patients received treatments including corticosteroids, antibiotics, hydroxychloroquine, or isotretinoin, with good improvement noted in one patient, moderate improvement in another, and stabilization in the third.

Conclusion: This phenotypic spectrum is a newly recognized entity that combines clinical and histological signs of FD and LPP. Early treatment is crucial to halt disease progression. The emergence of new variants within FDLPPPS, such as FD-frontal fibrosing alopecia, underlines the need for further case series to better characterize this spectrum.