Low prevalence of twisted hair in anorexia nervosa.

In a series of 30 patients affected by severe anorexia nervosa (AN) we examined hair samples to detect the prevalence of acquired pili torti (APT). True APT were not detected but in two cases (6.6%) twisted hair was observed. The first case was a 24-year-old woman with secondary amenorrhoea for 9 years, whose body mass index (BMI) was 12.2 kg/m2. She also had severe skin xerosis and hypertrichosis. The second case was a 24-year-old woman with secondary amenorrhoea for 1 year, whose BMI was 11.3 kg/m2. She also had severe skin and lip xerosis, severe effluvium, cystic acne, acrocyanosis, perimylolysis (severe erosion of the dentition) and scars due to cigarette burns on her forearms. Reviewing the literature we noticed that the largest series of pili torti--congenital and acquired--were published by authors from countries such as Israel and Egypt. We therefore hypothesize that, under the same conditions, a genetic factor may predispose to this hair shaft defect.