For the last six years, I’ve had this odd disruption of nail keratin production that started on my right pointer
finger. It looks like pitted lateral lines across the
nail, but not along the length of the nail. The nail bed on the anterior edge has slightly thickened and recedes over time, too.
Over time, the putting has come and gone, and the nail seems to be really hard and brittle. The symptoms spread to my left hand, but only the first finger, a year or two later. Same appearance.