Pili annulati with fragility: Electron microscopic findings of a case

Pili annulati (PA) is typically characterized by shinny beads seen along the hair shaft. PA is accepted to belong to the classification of hair shaft abnormalities without fragility. Herein, we described a 14-year-old, fair skin with dark-haired girl diagnosed as PA with fragility which was demonstrated by weathering features in electron microscopic examinations. The patient had shinny beaded, easily breakable hairs since the age of four. A few broken hairs were observed by a light pull test. Transmitted light microscopy revealed periodic dark bands in the hair shaft. These dark bands disappeared after application of 10% aqueous potassium hydroxide. Multiple cavities within hair shaft and severe cuticular damages representing the weathering pattern were observed in electron microscopic examinations. All these findings were found to be consistent with presence of fragility in PA. This case provides evidences of fragile hair structure of PA which may be due to pathological cavities within hair shafts.