At the 2023 AAD Annual Meeting, Maria K. Hordinsky, MD, FAAD, kicked off her session, “Frontal Fibrosing Alopecia (FFA) Pathogenesis—Present, Past and Future,” with the clinical difference between lichen planopilaris (LPP) and FFA. “FFA is unlike other scarring hair disorders but does not have a separate ICD-10-CM code, preventing research that could improve patient care,” she noted.

The following arguments were presented to the CDC as the need for a distinct FFA code:

• LPP is different form FFA
• LPP incidence is increasing globally
• Foundation for basic epidemiologic studies in the United States
• Monitor adherence to clinical management guidelines
• Track and improve patient care outcomes
• Potential equity implications

Dr Hordinsky shared, “If the proposal is approved, the earliest ICD-10-CM codes can be implemented in October 2024.”

Next, Dr Hordinsky talked about the clinical findings and mentioned a quote from the American Hair Research Society luncheon presentation, “Gene sequencing of skin biopsies and immune cell analysis of LPP, FFA, and central centrifugal cicatricial alopecia patients shows these disorders are indistinguishable from a gene analysis standpoint.”

Regarding the hormonal etiology of FFA, the incidence of FFA is unknown, “but experts agree that the number of women seeking diagnosis and help for this condition has markedly increased in recent years.”

In terms of genetics, a “genome-wide association study in FFA identifies 4 susceptible loci.”

Dr Hordinsky also discussed a possible association between FFA and leave-on facial skin products and sunscreens, “The high frequency of sunscreen use in patients with FFA, and the fact that many facial skin care products now contain sunscreens, raised the possibility of a causative role for sunscreen chemicals.”

Dr Hordinsky focused on neurogenic inflammation as a major contributor to the pathogenesis of FFA due to the following reasons:

• Calcitonin gene-related peptide is associated with lipid metabolism and is elevated in many chronic inflammatory conditions whereas peroxisome proliferator-activated receptor-gamma (PPARγ) is usually decreased.
• Substance P induces production and release of proinflammatory cytokines, such as IL-1, IL-6, and tumor necrosis factor-alpha in addition to PPARγ through the neurokinin-1 receptor.

In conclusion, Dr Hordinsky stated that “the preliminary findings of an increased aryl hydrocarbon receptor(AhR) expression in the epidermis of the nonlesion scalp in LPP and FFA is suggestive of an environmental role in the pathogenesis of these diseases.” She also added, “Further research, focused also on the nonlesional or ‘normal-appearing’ scalp areas is needed to better understand the AhR role in LPP and FFA.”

Reference
Hordinsky MK. FFA pathogenesis—present, past, and future. Presented at: AAD Annual Meeting; March 17–21, 2023; New Orleans, LA.