Twelve atopic patients with positive RAST and prick test reactions to a detergent enzyme (subtilisin) were challenged with detergents containing the enzyme in powdered form and in granulated form, and exposed to laundry washed in enzyme detergents. Eight patients displayed typical atopic symptoms after challenge with the detergent containing subtilisin in powder form. Four patients, three of them with a low RAST titre to subtilisin, had no reactions after challenge with this detergent. The detergent containing granulated enzyme caused very slight symptoms in the challenge test and no symptoms at all when handled in a way designed to simulate normal household exposure.
Smelling small pieces of cloth or sleeping on pillow-cases washed in enzyme detergent and then rinsed three times in fresh water did not cause any symptoms in the patients investigated. Exposure to fabric which had not been rinsed after washing in enzyme detergent caused slight rhinitis, or itching, in the nose or eyes in five of the most sensitive patients.
In a simulated washing procedure the enzyme containing detergent caused slightly more reddening or itching of the hands in five patients than the detergent without enzyme.
The findings indicate that even sensitized patients do not get atopic symptoms from normal handling of detergents with granulated enzymes or from short-term exposure to laundry washed in enzyme detergent and then adequately rinsed.