What does nail psoriasis typically show as?

Nail psoriasis is a condition characterized by specific changes in the appearance of the nails, with pitting and roughness being the hallmark features. The pitting presents as small, shallow depressions on the nail surface, which occur as a result of the underlying psoriasis affecting the nail matrix. This roughness can lead to an uneven texture that is distinctly visible when examining the nails.

In contrast to the other options, splinter hemorrhages are linear streaks of blood under the nail, often associated with different conditions; nail curvature could be indicative of various disorders affecting nail growth and shape, but it does not specifically present in psoriasis; and folded nail structures are not typically observed in psoriatic nails. Thus, the presence of pitting and roughness is uniquely characteristic of nail psoriasis, making it the correct answer in identifying this condition.