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TIPS FOR DIAGNOSIS
Diagnosis is clinical and specific scores could be helpful, but dermoscopy gives important informations for differential diagnosis.
Pitting, red lunula, trachyonychia and nail plate crumbling suggest nail matrix psoriasis.
Oil-drop sign (salmon patch), onycholysis, splinter hemorrhages and subungual hyperkeratosis indicate nail bed psoriasis.
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TIPS FOR TREATMENT
Topical therapies include steroids, vitamin D derivatives, tazarotene, topical calcineurin inhibitors, 5-fluorouracil.
Intralesional corticosteroid injections are an option if < of three nails are involved.
Systemic therapies are the best option if there are more affected nails and/or concomitant skin psoriasis. These include methotrexate, retinoids, apremilast and biologics.
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DON’T FORGET
Onycholysis is frequently associated with joint involvement.
Nail biting worsens fingernail psoriasis.
Dermoscopy can be helpful for the diagnosis of psoriasis when the clinical features are not typical.
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PITFALLS AND CAUTIONS
Toe nail psoriasis is more difficult to diagnose than fingernail psoriasis due to the presence of non-specific clinical features, such as isolated subungual hyperkeratosis.
Mycological examination is helpful in differential diagnosis between nail psoriasis and onychomycosis.
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EXPERT PEARLS
Distinguishing psoriatic pitting from alopecia areata pitting can be easier by remembering that in nail psoriasis pits are large and deep with irregular shape and distribution, while in alopecia areata pits are more superficial and regular with a geometric distribution.
Psoriatic onycholysis has a slightly dented margin surrounded by a yellow-orange band, while onycholysis due to onychomycosis shows a jagged proximal edge with spikes and longitudinal striae.
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PATIENT EDUCATION POINTS
Patients with nail psoriasis should avoid traumatizing nails with excessive manicuring to prevent Koebner phenomenon. Also, cleaning nails with sharp tools can worsen onycholysis. On the contrary, cutting the onycholytic plate will improve the passage of topical drugs on the nail bed and favor the attached growth of the nail plate.
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Psoriasis is a common and chronic skin disease characterized by epidermal hyperproliferation. Nail involvement in psoriasis is common with a prevalence of 50%–79% of patients and up to 80% of patients with psoriatic arthritis.1 Nail psoriasis in the absence of cutaneous disease is present in 5%–10% of psoriatic patients.2 Clinical manifestations of nail psoriasis depend on the affected site of the nail, which can be the nail matrix, the nail bed, the proximal nail fold and the hyponychium.3 Diagnosis is clinical, helped with specific scores, but dermoscopy gives important information for differential diagnosis. In doubtful cases, pathology can be necessary. The treatment of nail psoriasis is based on the severity and extension of the disease and is not standardized. Biologic therapies have also been introduced as a very successful treatment option.
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Psoriasis affects up to 3% of the general population, with a ...