Frontal fibrosing alopecia linked to allergic contact dermatitis with Cetrimonium bromide as potential allergen

Frontal fibrosing alopecia is a scarring alopecia that involves the frontal hairline and eyebrows. However, the aetiology remains controversial, recent publications indicate an association of frontal fibrosing alopecia and lichen planopilaris with allergic contact dermatitis.

The potential role of contact allergy in the pathogenesis of frontal fibrosing alopecia has been a topic of interest for several years now. Although the exact cause of frontal fibrosing alopecia is not definitive, there have been various studies pointing to the role of allergic contact dermatitis in FFA and LPP patients. The study cites the possible association of cetrimonium bromide allergy with FFA.

Cetrimonium bromide is an allergen that can be revealed in several personal care products. It is not routinely found in standard patch testing trays. Previous studies have demonstrated some improvement in FFA when avoiding relevant allergens. The exact role that these allergens play in LPP and FFA pathogenesis remains uncertain. Patch testing can often be helpful when dealing with dermatitis from a patch tester's point of view, and, even if not the sole cause of LPP or FFA, avoiding known allergens can often improve dermatitis and quality of life in patients.

CB is an allergen that the authors add to the growing list of allergens potentially associated with LLP and FFA and LPP. There is a need for more studies to determine the role of allergies in these disease processes.

Against the above background, Truel Cai, Washington University School of Medicine, St. Louis, MO, USA, and colleagues follow up on prior studies, expanding the number of allergens tested and drawing attention to the allergen cetrimonium bromide.

The study included 60 patients diagnosed with frontal fibrosing alopecia/lichen planopilaris. The researchers found the following:

• 83.3% of the cohort had a positive patch test, which was higher than the 2019 to 2020 North American Contact Dermatitis Group results, which showed only a 69.7% patch test positivity rate, suggesting a potential increased prevalence of allergic contact dermatitis in patients with FFA/LPP.
• 36.6% of the patients with FFA/LLP had positive patch testing for cetrimonium bromide.

"Cetrimonium bromide was the allergen that had the highest number of positive tests in the cohort, highlighting its potential as an allergen in frontal fibrosing alopecia patients," the researchers concluded.

Reference:

Cai T, Wang CX, Schlessinger DI, Sheinbein DM, Mann CM. Cetrimonium Bromide Patch Test Positivity Is Found With a High Frequency in a Cohort of Patients With Frontal Fibrosing Alopecia. Dermatitis. 2023 Jul 12. doi: 10.1089/derm.2022.0086. Epub ahead of print. PMID: 37437110.