A slate grey pigmentation of the hard palate and the subungual areas of the fingers and toes has been observed among the troops serving in the South West Pacific Area. The purpose of this investigation is to determine the prevalence and etiology of this condition.
In the hard palate, the pigment deposits vary in intensity and color from slate-grey to blue-black, first appear near the midline, and extend laterally to the gingival margins. There is usually a well-defined border. Several patients who had partial upper dentures had pigment deposited only in those areas untouched by the prosthesis. In the subungual areas, the early lesion is a slate grey patch or transverse line near the center of the nailbed. The pigmentation spreads and intensity increases but does not involve the distal quarter of the nailbed. In the most advanced cases almost the entire subungual tissue may be involved and there is direct extension into the adjacent skin along the lateral borders of the nails.