Psoriasis and lichen planus in nails

Nail psoriasis and nail lichen planus are chronic inflammatory conditions affecting the nails, often resulting in significant discomfort and impairment of quality of life. They are both immune mediated diseases that may affect also other body areas.

Nail psoriasis, depending on the anatomic area affected, presents with different clinical signs: irregular pitting, leukonychia, red spots in the lunula, nail plate thickening and crumbling are typical of nail matrix inflammation; salmon patches, onycholysis, splinter haemorrhages and subungual hyperkeratosis are typical of nail bed inflammation; paronychia is typical of nail folds inflammation. Due to the association with psoriatric arthritis, it is mandatory to always ask about pain and swelling and refer the patient to a rheumatologist if necessary.

Nail lichen planus has a typical longitudinal pattern of nail plate ridging and fissuring. Onycholysis and nail bed hyperkeratosis may also be present. Dorsal pterygium, anonychia and nail bed atrophy are, instead, less frequent. Contrary to psoriasis, nail lichen planus is a potentially scarring disorder so prompt and early treatment is mandatory to avoid permanent nail destruction.

Both conditions require comprehensive management strategies. Treatment should be selected according to the types and severity of clinical signs, number of affected nails, the extent of the diseases on other body surfaces (including joints for psoriasis), comorbidities, previous successful/unsuccessful treatments, patient age and, above all, quality of life.

Nail psoriasis treatments include topical therapies (corticosteroids, vitamin D analogs), systemic treatments (methotrexate, retinoids, biologics), and procedural interventions (intralesional corticosteroid or methotrexate injections). Nail lichen planus management primarily focuses on steroids (intralesional and systemic) and other agents such as retinoids or immunosuppressants are second line options. Future potential therapy, especially for nail lichen planus, may be systemic or topical JAK inhibitors, either as monotherapy or as adjunctive therapy.