The Future of Folliculitis Decalvans: What are the Scalp Microbiome Implications?

Folliculitis decalvans (FD) is a rare and challenging type of alopecia that leads to hair follicle inflammation, resulting in hair loss and scarring. Recent research suggests that FD has a unique microbiological signature and is associated with an impaired immune response, opening new avenues for understanding and treating this condition.

What We Know:

• FD typically presents as a slowly expanding, painful alopecic plaque on the vertex of the scalp, often in young males. Despite extensive research, the exact cause is unclear. However, several factors have been implicated, including genetic predisposition, Staphylococcus aureus colonisation, bacterial biofilms, compromised epidermal barrier integrity, congenital abnormalities in follicular orifices and dysfunction in the local immune system (Moreno-Arrones et al., 2023).

• As there is no definitive cure for FD, the goal of treatment is to stabilise the disease. Current therapeutic options include topical and systemic corticosteroids, antibiotics and isotretinoin. Case reports also highlight unconventional therapies such as topical tacrolimus, photodynamic therapy (PDT), dapsone, intravenous immunoglobulin (IVIG) and TNFα inhibitors, though these treatments are supported by limited evidence (Rózsa et al., 2024).

• Interestingly, while S. aureus colonisation has long been linked to FD, recent research suggests its role may have been overstated due to past limitations in microbiological techniques. New studies reveal that FD-affected hair follicles have a distinct microbiome, with key species including Ruminococcaceae, Agathobacter sp., Tyzzerella sp. and Bacteroidales vadin HA21 (Moreno-Arrones et al., 2023).

• Additionally, FD patients show significantly lower levels of IL-10, TNF-α and IL-6 after exposure to bacterial strains, indicating an impaired immune response that could contribute to the disease (Moreno-Arrones et al., 2023).

Industry Impact and Potential:

• A successful case study treated a therapy-resistant FD patient with CO2 laser-assisted PDT. PDT induces fibroblast apoptosis, generates reactive oxygen species and offers antimicrobial and anti-inflammatory effects. Applying CO2 laser before PDT enhances photosensitiser absorption by creating microscopic channels in the skin. This method, previously effective for hypertrophic acne scars (Rózsa et al., 2024).

Our Solution:

With over 20,000 microbiome samples and 4,000 ingredients in our extensive database, along with a global network of more than 10,000 testing participants, Sequential offers comprehensive services to assess the impact of products and formulations. Our commitment to preserving microbiome integrity makes us an ideal partner for developing scalp and hair care products, including those focused on FD and scarring treatments.

References:

Moreno-Arrones, O.M., Garcia-Hoz, C., Del Campo, R., Roy, G., Saceda-Corralo, D., Jimenez-Cauhe, J., Ponce-Alonso, M., Serrano-Villar, S., Jaen, P., Paoli, J. & Vano-Galvan, S. (2023) Folliculitis Decalvans Has a Heterogeneous Microbiological Signature and Impaired Immunological Response. Dermatology (Basel, Switzerland). 239 (3), 454–461. doi:10.1159/000529301.

Rózsa, P., Varga, E., Gyulai, R. & Kemény, L. (2024) Carbon-dioxide laser-associated PDT treatment of folliculitis decalvans. International Journal of Dermatology. 63 (9), 1256–1257. doi:10.1111/ijd.17136.