ans:Psoriatic nail disease
- Nail involvement is common in psoriatic patients, affecting up to 80% of patients at some point in their lives
- Nail psoriasis is common in psoriatic patients, particularly in patients with joint involvement.
The clinical findings associated with psoriatic nail disease correlate with the anatomical location of the nail unit that is affected by the disease.
The nail unit is composed of the nail plate, the nail bed, the hyponychium, the nail matrix, the nail folds, the cuticle, the anchoring portion of the nail bed, and the distal phalangeal bones.
- The nail plate is the largest component of the nail unit.
- The nail matrix gives rise to the nail plate.
- Any defect to the matrix results in onychodystrophy of the growing nail plate.
- The proximal nail matrix forms the dorsal portion of the nail plate, whereas the distal matrix forms the ventral part of the nail plate.
The clinical presentation may vary depending on the location and the severity of inflammation of the affected nail unit.
Nail Signs and Anatomic Site of Disease
- Nail matrix
Proximal: pitting, dystrophy:
- Pitting is the most common manifestation in fingernails.originate from focal psoriasis of proximal matrix.Pitting is a result of the loss of parakeratotic cells from the surface of the nail plate.when focal psoriasis may become more marked then a pit may enlarge & produce a hole in nail plate ,a sign termed ELKONYXIS.
- Beau lines: These lines are transverse lines in the nails due to intermittent inflammation causing growth arrest lines
- leukonychia: Leukonychia is areas of white nail plate due to foci of parakeratosis within the body of the nail plate.
- Nail bed
- Onycholysis: Onycholysis is a white area of the nail plate due to 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.
- Subungual hyperkeratosis: It is manifested as accumulated squames.in toenails subungual hyperkeratosis is the commonest finding.
- Nail plate crumbling: Nail plate weakening due to disease of the underlying structures causes this condition.
- Oil drop or salmon patch/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.
- Splinter hemorrhage:Splinter hemorrhage/dilated tortuous capillaries in the dermal papillae. Splinter hemorrhages are longitudinal black lines due to 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.
- Nail fold