<unk>  is a distinctive hair shaft abnormality that may occur sporadically, either in normal hair or with other hair shaft abnormalities, or regularly as a marker for Netherton's syndrome. The primary defect appears to be abnormal keratinization of the hair shaft in the keratogenous zone, allowing for intussusception of the fully keratinized and hard distal shaft into the incompletely keratinized and soft proximal portion of the shaft.
Trichorrhexis invaginata
Trichorrhexis nodosa
Steatocystoma simplex
Naegleriasis
Trichobacteriosis axillaris
Malum perforans
Sarcoptes scabiei
Dioctophyme renale