Effectiveness of clarithromycin in patients with yellow nail syndrome

BACKGROUND: Yellow nail syndrome (YNS) is a rare disease characterized by the triad of thickened, slow-growing yellow nails, lymphedema, and chronic respiratory manifestations. The cause of YNS is not known; however, it is suggested to be due to a congenital lymph abnormality. Since YNS is accompanied by chronic bronchial infection in more than half of patients, we hypothesized that treatment with clarithromycin (CAM) could be effective. We therefore evaluated the effectiveness of CAM against nail discoloration and respiratory manifestation in patients with YNS. METHODS: We conducted an observational study involving 5 patients with YNS who were treated at our institution between January 2005 and January 2016. CAM was prescribed for every patient. Patient demographic information, comorbidities, medications, chest radiographs, and clinical data such as nail color were extracted to evaluate clinical outcome. RESULTS: Mean patient age was 71.6 years, and 2 patients (40%) were male. Four patients had sinusitis, and 2 had rheumatoid arthritis. Regarding respiratory manifestations, 4 patients had sinobronchial syndrome and 2 had pleural effusion. Nail discoloration improved in every patient after CAM treatment. Four patients also experienced improvement in their respiratory manifestations. CONCLUSIONS: In patients with YNS, the anti-inflammatory activity of macrolides might improve their systemic inflammation. This improvement could help to reduce lymphedema and promote nail growth. TRIAL REGISTRATION: Ethical approval was provided by the institutional review board of the National Center of Global Health and Medicine (NCGM-G-002143-00), in January 2017. This study is retrospectively registered for UMIN Clinical Trial Registry (UMIN000028514) in August 4th, 2017.