Patch Testing with a Textile Dye Mix in a Baseline Series in Two Countries

Disperse dyes are the most common contact sensitizers among textile dyes. The main aim of this study was to investigate the outcome of patch testing with a textile dye mix 6.6%. A total of 2,049 patients from Sweden and 497 from Belgium were tested with the mix, consisting of Disperse (D) Blue 35, D Yellow 3, D Orange 1 and 3, D Red 1 and 17, 1.0% each, and D Blue 106 and D Blue 124, 0.3% each. Of the total number, 65 patients, 2.6%, tested positively to the mix, 4.2% of the Belgian patients and 2.1% of the Swedish patients. Patch testing with the mix 6.6% revealed significantly more patients with contact allergy compared with testing with a previous mix 3.2% (p<0.01). Contact allergy to the mix was significantly more common in the Belgian than in the Swedish patients

Methylisothiazolinones. Diagnosis and prevention of allergic contact dermatitis

Preservatives are biologically active substances which are required in water-based products/systems to prevent growth of micro-organisms. Kathon® CG (K-CG), one of several preservatives based on 5-chloro-2-methyl-4-isothiazolinon-3-one (MCI) and 2-methyl-4-isothiazolin-3-one (MI) has been shown to be a common sensitizer in dermatitis patients. The aims of the study were to find a method to demonstrate and quantify MCI and MI in various products; to isolate and identify the contact allergens in K-CG; to assess the sensitizing capacities of the allergens; to study the actual occurrence of MCI and MI in moisturizers; to investigate the occurrence and causes of occupational dermatoses in a plant where high concentrations of MCI and MI are handled; to find methods to prevent chemical burns and allergic contact dermatitis from MCI and MI. MCI and MI were demonstrated in various types of products by HPLC. Three allergens were isolated from K-CG and identified as MCI, MI and 4,5-dichloro-2-methyl-4-isothiazolin-3-one (45243-K-CG). Guinea pig maximization tests showed that MCI and 45243-K-CG were strong sensitizers and MI a weak sensitizer. At a plant where high concentrations of MCI and MI were used to produce binders and glues 9 of 51 present production workers (17.6 %) were sensitized to MCI and MI. Four of the 9 MCI- and MI-sensitized workers had spilled preservatives with high concentrations of MCI and MI on their skin resulting in chemical burns. Sodium bisulfite and glutathione were demonstrated to chemically inactivate MCI and MI

Variation in the amount of petrolatum preparation applied at patch testing.

The elicitation of a positive patch test reaction in a given individual depends upon the dose of the sensitizer applied, the patch test technique and the occlusion time. The dose is determined by the concentration and volume/amount of test preparation applied. If the same amount/volume of a test preparation is applied all the time with the same test technique (same area of skin) and occlusion time, it is appropriate to use concentration as a dose parameter. Most contact sensitizers are incorporated in petrolatum (pet.). With pet. as vehicle, it is impossible to repeatedly apply an exact volume/amount. This study was performed to investigate the inter- and intra-individual variation of pet. preparation applied at patch testing by 3 technicians. Weighing demonstrated that the 3 technicians had about the same precision in their pet. application. The investigation demonstrates that there is both an inter-individual (statistically significant) and intra-individual variation in the amounts of pet. applied at patch testing for the 3 technicians. Presently, there is no recommendation on what amount of pet. preparation to apply, which merits a decision to be taken based on thorough investigations on the appropriate volumes of pet. preparation to be applied in various patch test systems