Pili annulati | |
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Other names | Ringed hair disease |
Specialty | Medical genetics |
Pili annulati (also known as "ringed hair")[1] is a genetic trait in which the hair seems 'banded' by alternating segments of light and dark color when seen in reflected light.[1][2]: 767 [3]: 640 [4]
Pili annulati manifests during infancy or at birth. The clinical manifestation varies. Usually, the hair appears shiny and banded. Pili annulati usually just affects the scalp but can be present in other areas.
Pili annulati may be sporadic or inherited in an autosomal dominant fashion. Pili annulati can be diagnosed based on light microscopy or trichoscopy. Treatment is not needed.
Pili pseudoannulati is an anomaly of human hair that mimics pili annulati; however, the two differ in that the light bands of pili annulati are caused by internal effects, whereas the bright segments of pili pseudoannulati are caused by reflection and refraction of light by flattened, twisted surfaces of hair.[2]: 767