Improvements in pincer nail deformity occur earlier and last longer when acetylcysteine gel is added to an overcurvature‐correcting device: Results of a phase 3, multicenter, randomized, vehicle‐controlled, investigator‐blinded study

Abstract

Acetylcysteine (AC) destabilizes keratin and softens nails, reducing the time needed to correct pincer nail deformity with an overcurvature‐correcting device. The objective of this phase 3, multicenter, randomized, investigator‐blinded study was to evaluate the early and sustained therapeutic effectiveness and safety of 10% AC gel plus an overcurvature‐correcting device to treat pincer nails. Patients aged 12 years and older with hallux pincer nail were fitted with an overcurvature‐correcting device for 7 days, with a 24‐h application of AC gel (n = 40) or vehicle (n = 39) on day 1. The primary end point (achievement of a distal narrowed nail width ratio ≥70% on day 8) was met by 47.5% in the 10% AC group and 25.6% in the vehicle group (difference 21.9%; p = 0.0439). Secondary end points showed a greater tendency towards improvement with 10% AC. The nail correction effect was maintained for at least 12 weeks in the majority of AC‐treated patients, although the study duration was insufficient to assess the long‐term probability of recurrence. No AC‐related adverse events were reported. In conclusion, a single application of 10% AC gel combined with short‐term device use facilitated earlier correction of pincer nails compared with the device alone, with improvements maintained after device removal.