Persistence of Isothiazolinones in Clothes After Machine Washing

Abstract

BackgroundSensitization to methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) is a worldwide problem. Washing machine detergents are suspected to cause cutaneous symptoms in highly sensitized patients. Little is known about the persistence of isothiazolinones in clothes that have been washed.ObjectiveThe aim of the study was to analyze the possible persistence of MI, MCI, benzisothiazolinone, and octylisothiazolinone in common fabrics after machine washing.MethodsDifferent clothes (cotton, polyester, linen, and wool) were collected, and 4 types of wash were done (control, standard, standard + conditioner, and standard + double rinse). The samples were analyzed using ultrahigh-performance liquid chromatography.ResultsThe results showed that the concentrations of isothiazolinones were very low, independent of the type of material or wash. The highest levels were found in the control wash (hand wash), reaching a maximum of 0.4 ppm in the linen.ConclusionsOur findings suggest that it is not necessary to recommend that patients sensitized to MI avoid isothiazolinones in machine detergents or fabric conditioners or to double rinse. However, after using the detergent for hand washing (the control in our study), there may remain sufficient concentrations of isothiazolinones in clothes to produce symptoms in highly sensitized patients.

Trends in preservative allergy: Benzisothiazolinone emerges from the pack

“…In 11 cases of a facial dermatitis, 1 was attributed to household cleaning sprays, and this patient also had a background of atopic dermatitis. It has been suggested that there are minimal amounts of isothiazolinones present on clothing after washing 17 ; however, in practice this appears to potentially be an important source of exposure. Due to the nature of our service, we were not able to follow patients to establish if avoidance of BIT led to cessation of their dermatitis.…”

Contact sensitization to benzisothiazolinone: IVDK‐data of the years 2002 to 2021

“…It turned out, however, that their concentration generally is very low, so that after machine washing, BIT residues very probably do not pose a risk for elicitation of allergic contact dermatitis in sensitized individuals. 65 Our long-term data analysis of BIT sensitization showed a considerable up and down during the last 20 years (Figure 1). Without having detailed information on BIT use in craft and industry, we have no explanation for this course, neither for the high rates in 2003 to 2009, nor for the abrupt drop in 2010 and the following 5-year period of low sensitization rates.…”

“…Recently, the amount of isothiazolinones, including BIT, from detergents persisting in clothes after washing was investigated. It turned out, however, that their concentration generally is very low, so that after machine washing, BIT residues very probably do not pose a risk for elicitation of allergic contact dermatitis in sensitized individuals 65 …”