What isnail牛皮癣吗?
Nail psoriasis, also known as psoriatic naildystrophy, is due to牛皮癣involving thenail matrix或甲床,导致specific and non-specific clinical changes in the nail.
Nail psoriasis
Who gets nail psoriasis?
Nail psoriasis affects 90% of patients withchronicplaque牛皮癣at some time in their life. It is more common in adults with aprevalenceof up to 80%, compared to children in whom it has been reported in 7–13%. In the absence of skin or joint disease, psoriatic nail disease has been described in 5–10% of adults.
Psoriatic nail disease may be a risk factor thedevelopmentofpsoriaticarthritisand is often associated with prolonged severecutaneous牛皮癣.
Nail psoriasis can affect all races and age groups, and both sexes, although a male predominance has been reported in one large case series.
What causes nail psoriasis?
Psoriasis is amultifactorialsystemicdisease includinginflammationandepidermalhyperproliferation.
Nail psoriasis can involve the nail bed, nail matrix,hyponychium, and nail folds.
Theories include:
- Activation of theantimicrobialpeptideLL-37 byCandidaand thecytokineoverflow theory
- Increased expression ofinterleukin(IL)-10 in the affected nail bed compared to downregulation of IL-10 in psoriatic skinlesions
- Koebnerisation of psoriasis inonychomycosisor nailtrauma.
What are the clinical features of nail psoriasis?
Fingernails and toenails can be affected by nail psoriasis.
Psoriatic nail dystrophy can cause tenderness and pain, altered sense of fine touch, and difficulty picking up or manipulating objects such as shoelaces or buttons.
Clinical signs of nail matrix involvement
- Pitting
- Leukonychia
- Red spots in lunule
- Onychorrhexis(longitudinalnail ridge, split, orfissure)
- Beau lines(transverselines and ridges)
- Nail crumbling
Signs of psoriatic nail matrix involvement
Clinical signs of nail bed involvement
- Oil-dropsignand salmonpatch
- Onycholysis— typically with a pink zone proximally
- Subungualhyperkeratosis
- Splinterhaemorrhagesunder thedistalthird of thenail plate
Signs of psoriatic nail bed involvement
Other clinical signs of psoriaticnails
- Paronychiadue toperiungual牛皮癣
- Acrodermatitis continua of Hallopeau
- Twenty-nail dystrophy
Psoriatic nail dystrophy
[see alsoNail psoriasis images]
What are the complications of nail psoriasis?
- Secondary onychomycosis in the damaged nail plate
- Psychosocialeffectsimpacting social relationships and work-related activities
- Association with psoriatic arthritis and metabolicsyndrome
How is nail psoriasis diagnosed?
Nail psoriasis is usually diagnosed clinically in a patient with psoriatic arthritis and/or cutaneous psoriasis.
The severity of nail psoriasis can be estimated using the Nail Psoriasis Severity Index (NAPSI) in which each nail is divided intoquadrantsand scored for clinical signs to come up with a numerical score.
Nail clippings forfungalmicroscopyandcultureshould be taken as onychomycosis may precede or complicate psoriatic nail dystrophy, andimmunosuppressivemedications may be used in treatment.
Aproximalnail matrixbiopsyis occasionally needed to confirm the diagnosis of nail psoriasis, particularly in the absence of signs of psoriasis elsewhere or where only a single nail is affected and atumourcannot be excluded by other means. Biopsy can lead to permanent naildeformity.
What is thedifferential diagnosisfor nail psoriasis?
- Onychomycosis
- Nail trauma
- Lichen planusof the nail
- Parakeratosispustulosa
What is the treatment for nail psoriasis?
General measures
- Minimise nail trauma, keep affected nails short
- Treat associated onychomycosis first for at least three months
Specific measures
- Topicaltreatments
- Topical steroids— betamethasone dipropionate, clobetasol propionate
- Topicalcalcipotriol
- Topical calcineurininhibitors
- Systemic treatments
- Nonpharmacological treatments
What is the outcome for nail psoriasis?
Nail psoriasis has a variable response to treatment. The visible response may take weeks or months due to slow growth of the nail plate, andrelapsesare common.
Psoriatic nail disease can fluctuate in severity over time and can resolve spontaneously.