Raynaud's phenomenon following long-term repeated action of great differences of temperature.

The aim of these investigations was to study the effects of chronic thermal trauma on the development of vasomotor disturbances of the hands. The investigations were performed on 597 workers of the Fishing Company. The incidence of vasomotor disturbances of the hands was compared in: (1) workers not exposed to thermal trauma; (2) workers with long-term exposure to cold; (3) workers exposed to alternating influence of cold and heat. Superficial temperature was determined, finger plethysmography, capillaroscopy and hand arteriography were carried out. The investigations demonstrated that long-term alternating exposure to thermal trauma causes development of vasomotor disturbances. Clinical manifestations of Raynaud's syndrome were found in nearly 50% of female workers in fish processing plant whose hands were exposed to the action of ice and hot water. The incidence of vasomotor disturbances in workers exposed to long-term effects of cold was low.