Patch testing of patients allergic to Disperse Blue 106 and Disperse Blue 124 with thin-layer chromatograms and purified dyes.
BACKGROUND
Former investigations have demonstrated that patch test preparations containing Disperse Blue (DB) 106 and DB 124 are impure.


OBJECTIVE
To investigate the significance of impurities in preparations of disperse dyes with regard to contact allergy.


METHODS
21 patients allergic to DB 106 and/or DB 124 were tested with dilution series of commercial and purified DB 106 and DB 124. All patients were additionally tested with thin-layer chromatography (TLC) strips made from the commercial preparations containing DB 106 and 18 of them also with TLC strips containing DB 124.


RESULTS
13 of 21 and 12/18 patients tested positively to the strips of DB 106 and DB 124, respectively. Among these patients, 4/13 and 5/12, respectively, did not react to the main spot but reacted to other spots. Dilution series of purified DB 106 and DB 124 were positive in 10 patients each, while 16 and 15 patients, respectively, tested positively to the dilution series of the corresponding commercial disperse dye.


CONCLUSIONS
Approximately 25% of the patients, diagnosed as contact allergic to DB 106 and DB 124, only reacted to impurities in the patch test preparations. This has implications for diagnosis and prevention.
Ryberg
Kristina
K
Department of Occupational and Environmental Dermatology, Lund University, Malmö University Hospital, Malmö, Sweden. kristina.morgardt-ryberg@med.lu.se
Goossens
An
A
Isaksson
Marléne
M
Gruvberger
Birgitta
B
Zimerson
Erik
E
Persson
Lena
L
Bruze
Magnus
M
D000328:Adult; D000368:Aged; D001391:Azo Compounds / Q000633:toxicity*; D002855:Chromatography, Thin Layer; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D004340:Drug Contamination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010328:Patch Tests / Q000379:methods* / Q000592:standards; D012015:Reference Standards; D013548:Sweden
D001391:Azo Compounds; C069319:Disperse Blue 124; C049175:disperse blue 106