Evolving Surfactant Trends in the Thai Personal Care Market Over 15 Years and Their Association with Clinical Patch Test Reactivity.

BACKGROUND

Surfactants in personal care products are an established trigger of allergic contact dermatitis. However, regional data comparing market usage with sensitization rates remain limited.

OBJECTIVES

To examine 15-year trends in Thai surfactant prevalence and correlate them with clinical patch test reactivity.

METHODS

Surfactant prevalence in 6864 personal care products was surveyed using the Thai Contact Allergen Avoidance Program database (2010-2024). Concurrently, patch test results from 6603 patients were analyzed across 3 5-year intervals.

RESULTS

Cocamidopropyl betaine (CAPB) was the most prevalent surfactant overall (20.3%) and in cleansers (43.2%), whereas polysorbates predominated in non-cleansing formulations (17.9%). In cleansers, use of CAPB (P < 0.001), glucosides (P = 0.009), and cetrimonium chloride (P < 0.001) rose over time. Cetrimonium bromide, benzalkonium chloride, and CAPB showed the highest patch test positivity rates. Conversely, positivity declined for CAPB (P < 0.001), benzalkonium chloride (P = 0.007), lauryl glucoside (P = 0.019), and cocamide diethanolamine (P < 0.001).

CONCLUSIONS

The Thai market is shifting toward milder surfactants. A paradoxical decline in CAPB and lauryl glucoside sensitization occurred despite their rising prevalence. Continuous market monitoring is essential to keep patch test series and patient counseling relevant.