Active sensitization to dimethylthiocarbamylbenzothiazol sulphide: An unexpectedly strong rubber contact allergen

Background: The two dialkylthiocarbamyl benzothiazole sulphides, dimethyl-thiocarbamylbenzothiazole sulphide (DMTBS) and diethylthio-carbamylbenzothiazole sulphide (DETBS) were shown to be good markers of both thiuram and mercaptobenzothiazole sensitivity. Objectives: To investigate if DMTBS and/or DETBS could be better markers of contact allergy to common rubber additives than the ones currently used. Methods: Sixty-eight dermatitis patients were patch tested with DMTBS and DETBS, both at 1% in petrolatum (pet). Because of late reactions in 10 patients, these were retested to DMTBS and DETBS in serial dilutions. Tetramethylthiuram monosulphide (TMTM) 1.0% pet was also tested. Results: At the initial reading Days 3 and 7, no reactions were noted to DMTBS or DETBS. At retesting, 10 of the 68 (15%) patients reacted positively to lower concentrations of DMTBS than the initial test concentration. Seven of 8 also reacted to TMTM. Three of them had positive reactions to DEBTS. All 10 patients had reactions to more diluted solutions to DMBTS than to DEBTS (p = 0.0077; Mc-Nemar test, two-sided). Conclusions: Results speak for patch test sensitization to DMTBS with cross-reactivity to TMTM and also DEBTS. DMTBS and DEBTS could be new markers of rubber allergy but a safe test concentration must be found.