Occupational dermatoses among the cashew nut workers in Karnataka

Seventy five female workers employed in the cashew nut industry in Karnataka to slice off the outer hard shells from the nuts and thus exposed to the cashew nut shell oil had a characteristic cauterization type of reaction manifesting as brownish-black, thickened sheats of dead skin covering the dorsal as well as the palmar aspects of hands including the fingers, and feet. Smaller but similar lesions were also seen on those parts of the forearms, abdomen, neck and face which were not covered with clothes. The fingers were thinned and tapering and several nails of the hands and feet were thickened, discolored and eaten away. The other changes included loss of the dermatoglyphic patterns, maceration of the hands, small pits on the finger tips and pitted keratolysis seen in some cases only. Similar changes were also seen on the feet of both the male workers exposed to the same oil, in the section which extracts the oil from the sliced shells. In contrast, 29 female workers engaged to peel off the thin reddish covering on the cashew nut, had normal hands and feet, except for the two callosities on the flexural aspect of the proximal phalanx of the right middle finger, and proximal interphalangeal joint of the right index finger respectively, caused by the friction of the peeling knife. An open patch test with the cashew nut shell oil used as such in 37 workers produced a cauterization type of reaction in 32 workers irrespective of the nature of their duties, while the standard occluded patch test with 10% cashew nut shell oil in polyethylene glycol showed a mild cauterization type of reaction in only 6 workers. Patch tests with 1% and 0.1% concentrations of the shell oil were negative in all the workers. Two barrier creams tested to protect the workers from the cashew nut shell oil, produced reasonably effective results within a week.