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Pili bifurcati
Pili bifurcati
Clinical features
Pili bifurcati is a very common hair shaft disorder characterized by focal bifurcation of the hair shaft which, after a short distance, fuses to reform a single hair (Fig. 22.182). Each branch of the bifurcation is covered by its own cuticle. Pili bifurcati has been associated with mosaic trisomy 8 syndrome.1,2
Differential diagnosis Pili bifurcati can be distinguished from trichoptilosis because in the latter condition the bifurcations are not surrounded by a complete cuticle and are generally present in the distal segment of the hair shaft. In some cases, the bifurcation occurs in the proximal segment. Pili bifurcati should also be differentiated from pili multigemini in which multiple hair shafts emerge from a single follicular channel.1,3
Fig. 22.181 Uncombable hair syndrome (pili canaliculi): there is a longitudinal grooving within the hair (pili canaliculi) which contributes to the structural rigidity and clinical appearance. Courtesy of A.M. Aristizรกbal, MD, CES, Medellรญn, Colombia.
Fig. 22.182 Pili bifurcati: the hair is split within the longitudinal mid-zone and then rejoins. Courtesy of David de Berker, MD, Bristol Royal Infirmary, Bristol, UK.