Treatment of brittle nail with a hydroxypropyl chitosan-based lacquer, alone or in combination with oral biotin: A randomized, assessor-blinded trial.

We evaluated in a randomized, assessor-blinded, study the efficacy of a hydroxypropyl chitosan-based nail lacquer (HPC-NL) alone or in combination with oral biotin (HPC-NL + B) in the treatment of brittle nail syndrome (BNS). Fifty subjects (21 men; mean age 64 years) with BNS were enrolled. Twenty-six were randomly assigned to HPC-NL and 24 to the HPC-NL and biotin, 10 mg/daily (+B). Topical and oral treatments lasted for 4 consecutive months. The primary outcome was the evolution of the Onychodystrophy Global Severity Score (OGSS) assessing nail dystrophy, lamellar and longitudinal splitting, dyschromia, and pitting. At baseline, the OGSS, mean (SD), was 8.4 (2.1) in the HPC-NL group and 11.8 (2.3) in the HPC-NL + B group. The OGSS was significantly reduced during treatments in both groups. At Month 4, OGSS was reduced by 57% (HPC-NL) and 62% (HPC-NL + B). At the end of study period, the percentage of subjects with an OGSS reduction of ≥50% in comparison with baseline was 53% in the HPC-NL group and 80% in the HPC-NL + B group (p = .05). Both treatments were well tolerated. In subjects with BNS, HPC-NL alone is associated with a clinically relevant improvement of nail appearance. The combination of HPC-NL and oral biotin is associated with further clinical improvement.