Revisiting Contact Sensitization Among Patients With LPP/FFA: Cross-Sectional Findings From 55 Cases.

Area of Science:

• Dermatology
• Allergology
• Trichology

Background:

• Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are inflammatory scarring alopecia conditions.
• A potential link between topical product exposure and LPP/FFA development is debated, with inconsistent research findings.

Purpose of the Study:

• To determine the prevalence of delayed allergic reactions to common topical agents in patients diagnosed with LPP or FFA.
• To compare patch test results between LPP/FFA patients and a matched control group.

Main Methods:

• A real-world observational study conducted between 2018 and 2023.
• Patch testing utilized European Baseline, Cosmetics, Hairdressing, and Sunscreen series.
• Comparison involved 23 FFA patients, 32 LPP patients, and 171 controls undergoing identical testing.

Main Results:

• Positive patch test reactions in the European Baseline Series were 26% for FFA, 37% for LPP, and 56% for controls.
• Nickel and fragrance mix I were common allergens, but not more prevalent than in the general Israeli population.
• LPP/FFA patients exhibited fewer positive reactions to cosmetics, hair products, and sunscreens, with no clinically relevant reactions observed.

Conclusions:

• Patch test reactivity rates in patients with LPP/FFA do not surpass those found in the control group.
• The study suggests that common topical agents are unlikely to be a primary trigger for LPP/FFA development.