Folliculitis Decalvans in the Era of Antibiotic Resistance: Microbiology and Antibiotic Sensitivities in a Tertiary Hair Clinic

A Novel 3D Printed Model of Infected Human Hair Follicles to Demonstrate Targeted Delivery of Nanoantibiotics

Hair follicle-penetrating nanoparticles offer a promising avenue for targeted antibiotic delivery, especially in challenging infections like acne inversa or folliculitis decalvans. However, demonstrating their efficacy with existing preclinical models remains difficult. This study presents an innovative approach using a 3D in vitro organ culture system with human hair follicles to investigate the hypothesis that antibiotic nanocarriers may reach bacteria within the follicular cleft more effectively than free drugs. Living human hair follicles were transplanted into a collagen matrix within a 3D printed polymer scaffold to replicate the follicle's microenvironment. Hair growth kinetics over 7 days resembled those of simple floating cultures. In the 3D model, fluorescent nanoparticles exhibited some penetration into the follicle, not observed in floating cultures. Staphylococcus aureus bacteria displayed similar distribution profiles postinfection of follicles. While rifampicin-loaded lipid nanocapsules were as effective as free rifampicin in floating cultures, only nanoencapsulated rifampicin achieved the same reduction of CFU/mL in the 3D model. This underscores the hair follicle microenvironment's critical role in limiting conventional antibiotic treatment efficacy. By mimicking this microenvironment, the 3D model demonstrates the advantage of topically administered nanocarriers for targeted antibiotic therapy against follicular infections.

Clinical Characterization and Treatment Response of Folliculitis Decalvans Lichen Planopilaris Phenotypic Spectrum: A Unicentre Retrospective Series of 31 Patients

Folliculitis decalvans and lichen planopilaris phenotypic spectrum has been described as a form of cicatricial alopecia. The aim of this study is to describe the clinical and trichoscopic features and therapeutic management of this condition in a series of patients. A retrospective observational unicentre study was designed including patients with folliculitis decalvans and lichen planopilaris phenotypic spectrum confirmed with biopsy. A total of 31 patients (20 females) were included. The most common presentation was an isolated plaque of alopecia (61.3%) in the vertex. Trichoscopy revealed hair tufting with perifollicular white scaling in all cases. The duration of the condition was the only factor associated with large plaques (grade III) of alopecia (p = 0.026). The mean time to transition from the classic presentation of folliculitis decalvans to folliculitis decalvans and lichen planopilaris phenotypic spectrum was 5.2 years. The most frequently used treatments were topical steroids (80.6%), intralesional steroids (64.5%) and topical antibiotics (32.3%). Nine clinical relapses were detected after a mean time of 18 months (range 12-23 months). Folliculitis decalvans and lichen planopilaris phenotypic spectrum is an infrequent, but probably underdiagnosed, cicatricial alopecia. Treatment with anti-inflammatory drugs used for lichen planopilaris may be an adequate approach.

Diagnoseverzögerung, komorbide Hidradenitis suppurativa und die prognostische Bedeutung bakterieller Kulturen bei Folliculitis decalvans: eine Kohortenstudie

Hintergrund

Folliculitis decalvans (FD) ist eine primäre neutrophile vernarbende Alopezie, die häufig zu irreversiblem Haarverlust führt. Daten zu Epidemiologie, klinischen Merkmalen, Folgen und prognostischen Faktoren sind nur eingeschränkt verfügbar.

Ziel

Die Beurteilung einer Patientenkohorte mit FD sowie die Charakterisierung schwerer Krankheitsverläufe und prognostischer Faktoren, die eine Remission verhindern.

Patienten und Methoden

Diese retrospektive Kohortenstudie umfasste 192 Patienten, bei denen zwischen 2010 und 2020 an einem tertiären Zentrum eine FD diagnostiziert und die mindestens sechs Monate nachverfolgt wurden.

Ergebnisse

Die Diagnose wurde im Mittel um 22,2 (± 29,7) Monate verzögert gestellt. Komorbide Erkrankungen mit Okklusion der Haarfollikel waren häufig. In 45,6% der Fälle waren Bakterienkulturen positiv, am häufigsten mit Staphylococcus (S.) aureus. Schwere Krankheitsverläufe waren mit komorbider Hidradenitis suppurativa und positiver Bakterienkultur, insbesondere S. aureus, assoziiert. Bei 50,7% der Patienten kam es zu vollständiger Remission: Bei 32% innerhalb der ersten sechs Monate der Behandlung und bei 18,7% während der Nachkontrolle. Rezidive waren häufig. Negative Prognosefaktoren bezüglich der Remission waren jüngeres Alter und positive Bakterienkultur.

Schlussfolgerungen

Es besteht Bedarf hinsichtlich der Ausbildung von Dermatologen, um die Diagnoseverzögerung zu reduzieren. Das Screening von FD‐Patienten auf komorbide Hidradenitis suppurativa und Bakterienkulturen sind wichtig für die Behandlungsplanung.

Diagnostic delay, comorbid hidradenitis suppurativa and the prognostic value of bacterial culture in folliculitis decalvans: A cohort study

BACKGROUND

Folliculitis decalvans (FD) is a type of primary neutrophilic cicatricial alopecia often leading to irreversible hair loss. Data on its epidemiology, clinical features, outcomes, and prognostic factors are limited.

OBJECTIVE

To evaluate a cohort of patients with FD and identify characteristics of severe disease and prognostic factors which impede remission.

PATIENTS AND METHODS

This retrospective cohort study included 192 patients diagnosed with FD and followed for at least six months at a tertiary center between 2010 and 2020.

RESULTS

There was a diagnostic delay averaging 22.2 (± 29.7) months. Comorbid follicular occlusion disorders were common. Bacterial cultures were positive in 45.6% of the cases, with Staphylococcus (S.) aureus being the most common pathogen. Severe disease was associated with comorbid hidradenitis suppurativa and a positive bacterial culture, particularly S. aureus. 50.7% of patients experienced complete remission: 32% within the first six months of treatment and 18.7% later during follow-up. Relapses were frequent. Negative prognostic factors for achieving remission included younger age and a positive bacterial culture.

CONCLUSIONS

There is a need for the education of dermatologists to reduce the diagnostic delay. Screening FD patients for comorbid hidradenitis suppurativa and obtaining bacterial cultures is important for treatment planning.

Clinical Impact of Staphylococcus aureus Skin and Soft Tissue Infections

The pathogenic bacterium Staphylococcus aureus is the most common pathogen isolated in skin-and-soft-tissue infections (SSTIs) in the United States. Most S. aureus SSTIs are caused by the epidemic clone USA300 in the USA. These infections can be serious; in 2019, SSTIs with S. aureus were associated with an all-cause, age-standardized mortality rate of 0.5 globally. Clinical presentations of S. aureus SSTIs vary from superficial infections with local symptoms to monomicrobial necrotizing fasciitis, which can cause systemic manifestations and may lead to serious complications or death. In order to cause skin infections, S. aureus employs a host of virulence factors including cytolytic proteins, superantigenic factors, cell wall-anchored proteins, and molecules used for immune evasion. The immune response to S. aureus SSTIs involves initial responders such as keratinocytes and neutrophils, which are supported by dendritic cells and T-lymphocytes later during infection. Treatment for S. aureus SSTIs is usually oral therapy, with parenteral therapy reserved for severe presentations; it ranges from cephalosporins and penicillin agents such as oxacillin, which is generally used for methicillin-sensitive S. aureus (MSSA), to vancomycin for methicillin-resistant S. aureus (MRSA). Treatment challenges include adverse effects, risk for Clostridioides difficile infection, and potential for antibiotic resistance.

Scarring Alopecias: Pathology and an Update on Digital Developments

Primary cicatricial alopecias (PCA) represent a challenging group of disorders that result in irreversible hair loss from the destruction and fibrosis of hair follicles. Scalp skin biopsies are considered essential in investigating these conditions. Unfortunately, the recognised complexity of histopathologic interpretation is compounded by inadequate sampling and inappropriate laboratory processing. By sharing our successes in developing the communication pathway between the clinician, laboratory and histopathologist, we hope to mitigate some of the difficulties that can arise in managing these conditions. We provide insight from clinical and pathology practice into how diagnoses are derived and the key histological features observed across the most common PCAs seen in practice. Additionally, we highlight the opportunities that have emerged with advances in digital pathology and how these technologies may be used to develop clinicopathological relationships, improve working practices, enhance remote learning, reduce inefficiencies, optimise diagnostic yield, and harness the potential of artificial intelligence (AI).