Nine women with contact dermatitis due to a polyurethane elastomer (spandex) in their brassieres are reported. One woman also developed dermatitis from contact with spandex in her girdle. In all instances, the spandex reported to cause the dermatitis was Lycra, which has been reported not to cause spandex dermatitis. None of the patients had a positive patch-test reaction to the rubber accelerator, mercaptobenzothiazole (MBT), previously reported to give positive reactions in patients with spandex sensitivity. The substance in spandex causing hypersensitivity is unknown presently.
Carr RD. Spandex Dermatitis. Arch Dermatol. 1967;96(6):642-645. doi:10.1001/archderm.1967.01610060036004