Psoriatic onychodystrophy | |
---|---|
Other names | Psoriatic nails |
Psoriasis of the toenails | |
Specialty | Dermatology |
Causes | Psoriasis |
Differential diagnosis | Onychomycosis |
Treatment | Medications, radiation |
Frequency | 10% to 78% of those with psoriasis |
Psoriatic onychodystrophy or psoriatic nails is a nail disease. It is common in those with psoriasis, with reported incidences varying from 10% to 78%. Elderly patients and those with psoriatic arthritis are more likely to have psoriatic nails.[1]: 781–2
Psoriatic nails are characterized by a translucent discolouration in the nail bed that resembles a drop of oil beneath the nail plate.[2] Early signs that may accompany the "oil drop" include thickening of the lateral edges of the nail bed with or without resultant flattening or concavity of the nail; separation of the nail from the underlying nail bed, often in thin streaks from the tip-edge to the cuticle; sharp peaked "roof-ridge" raised lines from cuticle to tip; or separation of superficial layers of the nail followed by loss of patches of these superficial layers, leaving thin red nails beneath; or nail pitting–punctate changes along the nail plate surface.
The causes of nail psoriasis are unknown. It has been suggested that fungi may play a role.[3]
The Nail Psoriasis Severity Index (NAPSI) is a numeric, reproducible, objective, simple tool for evaluation of nail psoriasis.[4] It evaluates several signs separately, each on a 1–3 scale: pitting, Beau's lines, subungual hyperkeratosis and onycholysis. A 2005 study proposed a modified NAPSI scale for persons with psoriasis and named the title of their publication "Modification of the Nail Psoriasis Severity Index".[5] Then, in 2007, a study found that there was a high level of inter-rater variability of the 2003 NAPSI scale and proposed another index which was, like the 2005 article, a modification of the 2003 article, and was named modified NAPSI.[6]
A 2008 study found that Cannavo's qualitative system[7] correlated with NAPSI (P<0.001) and is less time-consuming.[8]
There is a risk of misdiagnosis with onychomycosis.
There exist numerous treatments for nail psoriasis but there is little information concerning their effectiveness and safety.[9] Treatments include topical, intralesional, radiation, systemic, and combination therapies.
Available studies lack sufficient power to extrapolate a standardized therapeutic regimen.[9]
As of April 2009, [needs update] an assessment of the evidence for the efficacy and safety of the treatments for nail psoriasis is in progress.[20]
A 2013 meta-analysis showed improvement of nail psoriasis with infliximab, golimumab, superficial radiotherapy, electron beam, and grenz rays compared to placebo.[22] Although systemic therapies have been shown to be beneficial, they may have serious adverse effects.[22] Topical treatments have not been well studied but may be beneficial.[22]
Active clinical trials investigating nail psoriasis:[23]