Two Negro children, one with psoriasis and one with eczema, developed hypopigmentation after treatment with polyethylene film (Polythene) applied over a steroid ointment. The area of depigmentation was limited to the skin covered by the polyethylene. Analysis of the film showed that it contained butylated hydroxytoluene as an antioxidant to prevent decomposition, and this seemed to be the responsible factor. In one patient, the skin gradually returned to normal eight weeks after stopping treatment; in the other, there was no sign of repigmentation four weeks after cessation of treatment.
Vollum DI. Hypomelanosis From an Antioxidant in Polyethylene Film. Arch Dermatol. 1971;104(1):70-72. doi:10.1001/archderm.1971.04000190072011