Pili canaliculi: a familial study

The pili canaliculi is a rare defect, first described in 1973 by Dupre’ et al. as “le syndrome des cheveux incoiffables. The condition, characterized by dry, frizzy, unruly, rough and blond hair probably is due to a keratinization defect. The disorder may be autosomal dominant, recessive with variable levels of penetrance or sporadic . Sometimes it is associated with ectodermal dysplasia , retinal dysplasia , dental anomalies, ichthyosis vulgaris, atopic eczema, progressive alopecia areata, hamartomas, lichen sclerosus, woolly hair nevus, brachydactyly, pili tort, digit and nail abnormalities. We report a three years old child with thin, blond, uncombable hairs, atopic dermatitis and onychoschizia. The maternal grandmother were said to have the same hairs in infancy. The mother had normal hairs. A study with scanning electron microscopy revealed the presence of typical triangular cross-sectional shapes with indentation, longitudinal grooving and flattening of the hair surfaces. These morphologic features were discontinuous and found on different surfaces along the length of the hair. The overlying cuticle of the hair was instead normal. These findings were present in many hairs of child and grandmother, but in few hairs of the mother. The repeating of this peculiar aspect in the hairs within this family suggests that inheritance pattern is autosomal dominant. Moreover, the characteristic hair morphology can be observed in relatives, without hair abnormality. Since, the disorder could be associated to other extracutaneous abnormalities, it is indispensable a follow-up of the affected patient.