Pili Annulati with Multiple Fragile Hairs

The document reports a case of a 25-year-old man with Pili Annulati (PA), a hair condition characterized by alternating light and dark bands on the hair shaft, who presented with multiple fragile hairs and a history of heavy hairdryer use. Physical and dermoscopic examination revealed black hair shafts with alternating light brown color and multiple small white-gray spots. Microscopic examination showed air-filled spaces within the hair shaft, and scanning electron microscopy revealed loss of cuticle, indentations, longitudinal fissuring, and exposure of the cortex microfibers, resembling trichorrhexis nodosa. The study suggests that the air-filled spaces in PA may contribute to hair fragility and susceptibility to environmental trauma, such as damage from frequent hairdryer use. The authors conclude that the patient's heavy use of a hairdryer could have exacerbated the underlying PA, leading to increased hair fragility.