<unk>  may have a genetic basis but appears to be precipitated by environmental factors. Among Caucasians the defect often appears at the ends of the hair shaft with splitting of the ends, thinning and whitish discoloration. These conditions are directly related to environmental causes such as "perming", blow drying, aggressive hair brushing, and excessive chemical exposure. In some cases,<unk>  may be caused by an underlying disorder such as argininosuccinic aciduria, Menkes' kinky hair syndrome, Netherton's syndrome, hypothyroidism, or trichothiodystrophy.
Trichorrhexis nodosa
Trichorrhexis invaginata
Steatocystoma simplex
Leontiasis ossea
Naegleriasis
Acne conglobata
Dioctophyme renale
Elephantiasis nostras