We report 4 new cases presenting with the characteristics of a recentl
y described pilar dysplasia entitled 'diffuse partial woolly hair'. Tw
o of our cases were familial (mother and daughter), while the 2 other
were sporadic. Scalp hair of all the patients exhibited two hair shaft
populations intermingled throughout the scalp. The first hair type wa
s straight, normally pigmented and of normal length, while the second
type was wavy and the shafts were hypopigmented, thinner, shorter and
easily pluckable. One of our patients presented with a diffuse hair th
inning due to a progressive loss of wavy hairs. Under reflected light,
both hair populations displayed alternating dark and bright segments.
Scanning-electron microscopic analysis of straight and wavy hairs rev
ealed comparable lesions: torsions, angular kinks, weathering as well
as grooved segments alternating with the normal ones. These changes we
re the most severely expressed in the shortest and the waviest hairs.
Taken together, the clinical and microscopic characteristics of this p
ilar dysplasia justify its introduction as a separate entity into the
woolly hair group.