BACKGROUND: Despite numerous advances in the therapeutic management of cutaneous psoriasis, there is a lack of standardized therapeutic regimens for psoriatic nail disease.OBJECTIVE: An open, non-randomized, unblinded study was designed to evaluate the efficacy and safety of adalimumab in the treatment of nail psoriasis.PATIENTS/METHODS: Seven patients suffering from severe plaque-type psoriasis and 14 with psoriatic arthritis and cutaneous psoriasis with concomitant nail involvement were enrolled into the study. The applied dose regimen of adalimumab was the same as the one recommended for cutaneous psoriasis. Outcome measures were assessed at baseline and at weeks 12 and 24 using the Nail Psoriasis Severity Index (NAPSI). Patients also filled in a Greek translation of the international onychomycosis-specific questionnaire to assess the impact of the nail improvement on their quality of life.RESULTS: All 21 patients completed the study and were eligible for statistical analysis. Significant improvement was recorded after the eighth injection. Mean NAPSI (NAPSIm) at baseline was 10.57 +/- 1.21 for the fingernails and 14.57 +/- 2.50 for the toenails in patients with just cutaneous psoriasis and 23.86 +/- 2.00 for the fingernails and 29.29 +/- 2.87 for the toenails in patients with psoriatic arthritis. NAPSIm at week 12 was 5.57 +/- 0.78 for the fingernails and 9.57 +/- 2.17 for the toenails in patients with just cutaneous psoriasis and 12.86 +/- 1.05 for the fingernails and 19.21 +/- 2.07 for the toenails in patients with psoriatic arthritis. NAPSIm after 24 weeks of treatment was 1.57 +/- 0.20 for the fingernails and 4.14 +/- 1.58 for the toenails in patients with cutaneous psoriasis and 3.23 +/- 0.32 for the figernails and 10.00 +/- 1.40 for the toenails in patients with psoriatic arthritis. Treatment was well tolerated with minimal and temporary side-effects limited to the site of injection. All patients were satisfied, while marked improvement in their quality of life was recorded based on the reduction of the scores obtained from the international quality of life questionnaire.CONCLUSIONS: Despite the lack of a control group, our results demonstrate a beneficial effect of adalimumab on psoriatic nail disease.