Distal interphalangeal predominant PsA involves inflammation of the distal joints (such as those in the fingers and/or toes closest to the nail bed) and affects about 1 in 10 individuals with PsA. Since the joints closest to the nail beds are most commonly affected, nail changes are especially frequent in this form of PsA. Some common nail changes include pitting, ridges, crumbling, or separation from the nail.