Circle Hairs in a Patient with Multiple Myeloma.

Circle hair is a rare body-hair disorder of unknown etiology, typically characterized by perfectly or nearly perfectly coiled hair located below the cornified layer of the skin. Its main histopathological features are dilated hair-follicle infundibula and entrapped hair shafts. After its first description in 1963, there have only been a small number of reported cases, and its pathophysiology remains unclear. Herein, we report a case of an 80-year-old woman with skin lesions and abnormal hairs on both legs. We also propose a possible mechanism of her circle hairs: it may have occurred as an effect of her acquired ichthyosis secondary to her underlying multiple myeloma. There is no specific treatment for circle hairs, and reassurance that it is a harmless condition is sufficient. We prescribed a topical humectant and keratolytic agent to moisten the skin and lessen the hair entrapment, which resulted in clinical improvement. As the pathogenesis of the disease is unknown, further studies are warranted.