Concomitant Allergic Contact Dermatitis and Frontal Fibrosing Alopecia: A Potential Trigger for Relapse or Onset?

Introduction: Frontal fibrosing alopecia (FFA) is a primary lymphocytic scarring alopecia predominantly affecting postmenopausal women, with histopathological similarities to lichen planopilaris but distinct clinical features. The global rise in FFA cases over the past 15 years points to potential environmental factors. Case Presentation: This study presents 2 FFA cases: one experiencing a flare-up and another with disease onset, both associated with allergic contact dermatitis. Case 1 involved a 58-year-old female with a flare-up linked to a nickel allergy, while case 2 described a 60-year-old female with new-onset FFA following exposure to hair dye allergens. Discussion: Environmental particles, such as titanium dioxide found on hair shafts of FFA patients, are hypothesized to contribute to FFA through photocatalytic activity causing tissue damage and inflammation. Studies indicate a higher use of facial moisturizers and sunscreens among FFA patients, with frequent positive patch test reactions to allergens in personal care products. These allergens may disrupt hair follicle immune privilege, leading to inflammation, fibrosis, and follicular destruction. Understanding the role of environmental factors in FFA pathogenesis may improve management strategies, emphasizing allergen avoidance and targeted treatments.