Fast Five Quiz: Fingernail and Toenail Conditions

William James, MD


February 07, 2020

The clinical findings associated with psoriatic nail disease correlate with the anatomical location of the nail unit that is affected by the disease. The clinical presentation may vary depending on the location and the severity of inflammation of the affected nail unit.

The following may be observed in patients with nail psoriasis:

  • Oil drop or salmon patch of the nail bed: This lesion is a translucent, yellow-red discoloration in the nail bed, resembling a drop of oil beneath the nail plate. This patch is the most diagnostic sign of nail psoriasis.

  • Pitting of the proximal nail matrix: Pitting is a result of the loss of parakeratotic cells from the surface of the nail plate.

  • Beau lines of the proximal nail matrix: These are transverse lines in the nails caused by intermittent inflammation, leading to growth arrest lines.

  • Leukonychia of the midmatrix: Leukonychia are areas of white nail plate caused by foci of parakeratosis within the body of the nail plate.

  • Subungual hyperkeratosis of the hyponychium: Subungual hyperkeratosis affects the nail bed and the hyponychium. Excessive proliferation of the nail bed can lead to onycholysis.

  • Onycholysis of the nail bed and nail hyponychium: Onycholysis is a white area of the nail plate caused by a functional separation of the nail plate from its underlying attachment to the nail bed. It usually starts distally and progresses proximally, causing a traumatic uplifting of the distal nail plate. Secondary microbial colonization may occur.

  • Nail plate crumbling: Disease of the underlying structures causes nail plates to weaken.

  • Splinter hemorrhage/dilated tortuous capillaries in the dermal papillae: Splinter hemorrhages are longitudinal black lines caused by minute foci of capillary hemorrhage between the nail bed and the nail plate. This is analogous to the Auspitz sign of cutaneous psoriasis, which is the pinpoint bleeding seen beneath the psoriatic plaques.

  • Spotted lunula/distal matrix: This is an erythematous patch of the lunula.

Read more about nail psoriasis.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: