Exclusion of Disperse Orange 3 From the Textile Dye Mix Present in the Baseline Patch-Test Series: A Study by the International Contact Dermatitis Research Group

Background: The textile dye mix (TDM) 6.6% in petrolatum contains Disperse Blue (DB) 35, Disperse Yellow 3, Disperse Orange (DO) 1 and 3, Disperse Red 1 and 17, and DB 106 and 124. The most frequent allergen in TDM-positive patients is DO 3. Around 85% of para-phenylenediamine (PPD)-allergic dermatitis patients have been positive to DO 3. There has been a discussion to exclude DO 3 from TDM 6.6% because of strong simultaneous reactions to TDM and PPD. Objective: To study if DO 3 can be excluded from TDM 6.6%. Methods: Patch tests were performed on 2951 dermatitis patients with TDM 6.6%, TDM 7.0% (without DO 3 but with the other disperse dyes at 1.0% each), DO 3 1.0%, and PPD 1.0% pet. Results: Contact allergy to TDM 6.6% was 4.3% and to TDM 7.0% was 3.5%. Sixty-three out of 69 DO 3-positive patients were positive to PPD. The 102 patients positive to TDM 7.0% plus the 28 patients positive to PPD and TDM 6.6% but negative to TDM 7.0% were 130, outnumbering the 127 positive to TDM 6.6%. Conclusion: TDM 7.0% can replace TDM 6.6% in the International Contact Dermatitis Research Group baseline series, since TDM 7.0% together with PPD 1.0% will detect patients with textile dye allergy.