Abstract: Objective: To analyze the clinical characteristics and patch test results of adverse reactions induced by special use cosmetics. Methods: A retrospective analysis was conducted on cases of adverse reactions caused by special use cosmetics reported to our hospital from October 2022 to January 2026. Data on patient demographics, clinical features, suspected cosmetic products, and patch test results were summarized and analyzed. Results: A total of 603 cases of adverse reactions to special cosmetics were identified, predominantly in females (85.41%). Cosmetic contact dermatitis was the most common reaction type (96.68%). Hair dye products accounted for the highest proportion of suspected products (34.33%), with most purchased online (73.13%). An analysis was conducted on 77 patients who completed the patch test.The top five allergens identified by patch testing were gallate mixture (16.67%), diazolidinyl urea (12.90%), thimerosal (12.50%), sorbitan monooleate (Span-80) (11.11%), and decyl glucoside (10.53%). Patients with multiple sensitizations (≥3 positive allergens) accounted for 14.29% and had poorer outcomes, with only 27.27% achieving complete remission or cure. Conclusion: Adverse reactions to special cosmetics predominantly manifest as facial contact dermatitis in females, with hair dye products being the main culprit. Stricter regulation of online special cosmetics is needed. Patch testing is valuable for identifying allergens, and for patients with multiple sensitizations, skin barrier repair and allergen avoidance should be prioritized.

Key words: patch test, special use cosmetics, adverse reactions to cosmetics