These nail changes are seen in
Fingernail involvement in psoriasis appears as punctate pitting, onycholysis, nail thickening, or subungual hyperkeratosis The nail matrix will have pitting, which appears as punctate depressions that are small, shallow, and various shapes and sizes. Characteristically, they are isolated and deep, though they may occur as regular lines or grid-like pattern. The nail is dull, rough, and fragile The nail bed may have "oil" spots, which are oval, salmon-coloured nail beds, and there may be onycholysis secondary to "oil" spots affecting hyponychium medially or laterally. Secondary infections may occur. The nail plate may become raised off the hyponychium (subungual hyperkeratosis). The most frequent signs of nail matrix disease are pitting, leukonychia, crumbling, and red spots in the lunula, whereas salmon patches or oil spots, subungual hyperkeratosis, onycholysis, and splinter hemorrhages represent changes of nail bed psoriasis Ref: Harrison 19e pg: 347; Fitzpatrick dermatology
Lichen planus
Psoriasis
Darier disease
Onychomycosis
Papulosquamous disorders