Dynamics of psoriatic trachyonychia during low-dose cyclosporin A treatment: A pilot study on onychochronobiology using optical profilometry

Background: The effect of low-dose cyclosporin a (CsA) on psoriatic onychopathy has not yet been thoroughly studied, Purpose: To measure the changes in nail surface contours during a 3-mg/kg/day CsA therapy. Method: In vivo optical profilometry was performed at regular intervals in 5 psoriatic patients to derive mean roughness (Ra) and mean depth of roughness (Rz) values of nails. Segmental Rz served to evaluate long-term onychochronobiology. Results: Untreated psoriatic trachyonychia was best described by Rz which showed large interindividual differences. A progressive improvement in segmental Rz took place after 2-3 months of maintenance therapy. Conclusion: CsA improves psoriatic onychopathy after an apparent lag phase. The maximum improvement may only be reached during the CsA tapering phase.