4,4′-Thiobis(2-tert-butyl-5-methylphenol), an antioxidant in medical devices that may cause allergic contact dermatitis

Background: Antioxidants in medical devices, added to protect polymers or adhesives, may also cause contact dermatitis in some individuals. Objectives: To present data on sensitization to 4,4′-thiobis(2-tert-butyl-5-methylphenol), an antioxidant detected in some types of medical devices, for six patients that experienced eczematous reactions to different medical devices. Methods: Patch testing with 4,4′-thiobis(2-tert-butyl-5-methylphenol), 1% pet was performed. Gas chromatography-mass spectrometry (GC-MS) was used for identification of 4,4′-thiobis(2-tert-butyl-5-methylphenol) in different medical device products. Results: Six patients with contact allergy to 4,4′-thiobis(2-tert-butyl-5-methylphenol) also had relevant contact allergic reactions to medical devices containing the antioxidant. The presence of the antioxidant in products was detected using GC-MS analysis. Conclusions: The antioxidant 4,4′-thiobis(2-tert-butyl-5-methylphenol) may cause allergic contact dermatitis after exposure to different medical devices.