Many, affecting 10–55% of patients and <5% of those with no other cutaneous manifestation. If untreated,
they can lead to functional and social impairment. They are especially common in psoriatic arthritis (53–86%
of patients), even though only 10–20% of all psoriatic patients have the arthritis.
-Pitting
-Oil spot or salmon patch/nail bed: The most diagnostic nail sign; it consists of a translucent,
yellow-red discolored patch in the nail bed, resembling a drop of oil beneath the plate.
-Beau’s lines in the proximal nail matrix
-Leukonychia: Areas of white nail plate; due to parakeratotic foci in the mid-matrix
-Subungual hyperkeratosis: Excessive proliferation of the nail bed that can lead to onycholysis
-Onycholysis
-Nail plate crumbling: Weakened nail plate, bed, and matrix from diseased underlying structures
-Splinter hemorrhages: Longitudinal black lines due to tiny capillary hemorrhages between the nail bed
and plate; analogous to Auspitz sign (pinpoint bleeding under the psoriatic plaque) Dilated tortuous capillaries in the dermal papillae
-Spotted lunula: Distal matrix involvement characterized by erythema of the lunula
they can lead to functional and social impairment. They are especially common in psoriatic arthritis (53–86%
of patients), even though only 10–20% of all psoriatic patients have the arthritis.
-Pitting
-Oil spot or salmon patch/nail bed: The most diagnostic nail sign; it consists of a translucent,
yellow-red discolored patch in the nail bed, resembling a drop of oil beneath the plate.
-Beau’s lines in the proximal nail matrix
-Leukonychia: Areas of white nail plate; due to parakeratotic foci in the mid-matrix
-Subungual hyperkeratosis: Excessive proliferation of the nail bed that can lead to onycholysis
-Onycholysis
-Nail plate crumbling: Weakened nail plate, bed, and matrix from diseased underlying structures
-Splinter hemorrhages: Longitudinal black lines due to tiny capillary hemorrhages between the nail bed
and plate; analogous to Auspitz sign (pinpoint bleeding under the psoriatic plaque) Dilated tortuous capillaries in the dermal papillae
-Spotted lunula: Distal matrix involvement characterized by erythema of the lunula