Ringed Hair (syns: Pili Annulati, Leukotrichia Annularis)
An autosomal dominant condition (the gene passed on through one parent) was first described in 1846 and thereafter in 1867.
In this rare hair-shaft condition naturally pigmented bands measuring 2 – 6 mm appear randomly and alternate with white bands along the hair-shaft. This ringed appearance is present from birth, it may be localised or extend along the length of the hair-shaft. It may affect any number of hair-shafts.
It is suggested that the apparent de-pigmention may be due to air cavities between cortical cells reflecting light. Others theories postulate ‘failure or absence of pigment formation before conification’
Ringed hair is not usually synonymous with structural weakness.
The study of de-pigmented hair-shafts under low and high powered magnification reveals the presence of minute bright spots adjoining the nuclei of cortical cells reminiscent of light reflected from glass. They have been found to remain after boiling or soaking the hair-shaft in glycerine or canada balsam.
The condition which should not be confused with the shimmering associated with twisting (as in trichokinesis) or constrictions (as in Monilethrix) may be observed in other family members.
There is no treatment for this condition.
B Stevens PhD FTTS