Skin irritancy and sensitivity to laundry detergents containing proteolytic enzymes. Part I.
In the present study the contact irritative--eczematogenic--effect of alkaline protease enzymes (PE) contained in syndet laundry detergents has been investigated. The method employed was the occlusive epicutaneous test (ET) involving the use of increasing serial dilutions of PE and various times of exposure. The tests were made on sympton-free skin, on skin showing premorbid or slight irritative changes, on skin previously acid- or base-treated, in the presence of increased skin permeability and following the skin stripping method. The results obtained in the 912 test series indicate that the PEs tested ("Tenzym prilled" Grindstedvoerkek, and "Maxatase" Gist-Brocases) caused no irritation or other damage to the intact or slightly lesioned skin even in response to close contact lasting several days. When as a result of increased irritation, or for other reasons, the PEs may be assumed to penetrate into the subcorneal layers, they may exert a proteolytic effect, as manifested in the increasing number of positive ETs. In such cases the PE concentrations exceeded by far those employed in the commercial detergents. It is most likely that the skin changes noted in connection with the use of bioactive laundry detergents are due not to the PE content of these detergents, but to other factors.