A 12-year-old girl presented with a 2-year history of progressive hair loss involving the top of the scalp. She also complained of partial loss of eyebrows. Family history was unremarkable. Examination revealed mild widening of the central parting, suggesting a diagnosis of female pattern hair loss (Figure, A) and alopecia of the eyebrows and lower eyelashes (Figure, B). Dermoscopy of the scalp showed a few characteristic monilethrix hair shafts characterized by uniform elliptical nodes, separated by intermittent constrictions. Broken hair shafts at internode levels were also evident (Figure, C). Dermoscopy of the eyebrows was also diagnostic for monilethrix. The term monilethrix derives from both the Latin monile (necklace) and the Greek thrix (hair). The hair shaft has a beaded appearance due to the presence of elliptical nodes that have the diameter of normal hair and are medullated, regularly separated by internodes that are narrow, devoid of medulla and are the site of fracture.1Tosti A. Torres F. Dermoscopy in the diagnosis of hair and scalp disorders.Actas Dermosifliogr. 2009; 100: 114-119Crossref PubMed Scopus (35) Google Scholar, 2Rakowska A. Slowinska M. Kowalska-Oledzka E. Rudnicka L. Trichoscopy in genetic hair shaft abnormalities.J Dermatol Case Rep. 2008; 2: 14-20Crossref PubMed Google Scholar It is an autosomal dominant disorder, with variable expression, due to mutations of the human basic hair keratins hHb6 and hHb1. The hair is dull, fragile, and breaks easily, especially in the sites of friction such as the nape and occipital areas. Follicular keratosis of the affected scalp and keratosis pilaris are also typical. The severity of monilethrix considerably varies even among members of the same family and may range from an almost normal scalp, to total alopecia.3Gebhardt M. Fischer T. Claussen U. Wollina U. Elsner P. Monilethrix-improvement by hormonal influences?.Pediatr Dermatol. 1999; 16: 297-300Crossref PubMed Scopus (26) Google Scholar, 4Jain N. Khopkar U. Monilethrix in pattern distribution in siblings: diagnosis by trichoscopy.Int J Trichology. 2010; 2: 56-59Crossref PubMed Scopus (22) Google Scholar In this case, the disease was mild and went unnoticed until adolescence. The correct diagnosis was indicated by dermoscopy that easily evidenced the few hairs affected by the abnormality. The parents were advised to avoid trauma to scalp hair and informed that the condition may spontaneously improve with age, whereas no effective treatment is currently available.3Gebhardt M. Fischer T. Claussen U. Wollina U. Elsner P. Monilethrix-improvement by hormonal influences?.Pediatr Dermatol. 1999; 16: 297-300Crossref PubMed Scopus (26) Google Scholar, 5Finley E. Ertle J.O. Marschall S. Alopecia in a 19-month-old boy.Arch Dermatol. 1994; 130: 1055-1056Crossref PubMed Scopus (2) Google Scholar