trichotillomania ( ttm ) is a type of impulse control disorder , characterized by recurrent pulling of hair , which leads to pleasure and relief of tension . prevalence rates of this condition range between 1% and 13.3% , with initial mean age of onset between 10 years and 13 years and a notable peak at 12 - 13 . the disease leads to hair loss , which may sometimes be severe and lead to significant social and functional impairment . the etiology of the disease is still unknown , although some have suggested a genetic component . this was based on a limited number of reports on familial hair pulling and one twin concordance study . we hereby describe a case of familial ttm in three generations , thereby underlining the familial basis for this disorder . a 13-year - old male presented with 1-year history of focal hair loss in the mid - frontal scalp . he was previously treated with local steroids for presumed alopecia areata , with no improvement . examination revealed a patchy area of hair loss , with several short broken hairs of varying lengths [ figure 1a ] . on dermoscopy examination of the scalp , we found the typical features of ttm , including short hairs with trichoptilosis , broken hair ( different lengths ) and black dots [ figure 1b ] . histological examination showed trichomalacia with irregularly shaped hair follicles and melanin pigment casts [ figure 1c and d ] . upon further questioning , the father admitted repeated pulling of his beard hairs since puberty , with mild - to - moderate severity of symptoms . the 60-year - old paternal grandfather also suffers from severe recurrent hair pulling of his beard since puberty , which sometimes precludes him from leaving home . ( a ) patchy area of hair loss on the scalp , with several short broken hairs of varying lengths ; ( b ) dermoscopy of the scalp lesion demonstrating short hairs with trichoptilosis , broken hair ( different lengths ) and black dots ; ( c - d ) low ( c ) and high ( d ) magnification histopathology of the scalp lesion demonstrating the presence of trichomalacia with irregularly shaped hair follicles ( arrows , c ) and melanin pigment casts ( arrows , d ) it is believed that the etiology of ttm is complex , involving biological , psychological and social factors . this was based on a limited number of reports on familial ttm and one twin concordance study . in this twin study , respective concordance rates for monozygotic and dizygotic twin pairs were 38.1% and 0% for diagnostic and statistical manual of mental disorders iv criteria and 58.3% and 20% for non - cosmetic hair - pulling , leading to a heritability estimate of 76.2% . rare variations in slitrk1 were associated with disorders of the obsessive - compulsive spectrum and among them also ttm . mouse models also suggested a relationship between mutations in hoxb8 and sapap3 and ttm - like behavior in mice . although several cases of familial ttm have been reported , to our knowledge , this is the first report of ttm in a three - generation family . this report strengthens the possibility that ttm is a genetic disease , probably with a complex inheritance pattern . it also underlines the importance of proper family history taking when examining a ttm patient .