BACKGROUND Nonscarring alopecia differs from scarring alopecia on pathologic examination by the preservation of follicular units and lack of follicular dropout. However, long-standing cases of active nonscarring hair loss can show follicular dropout on pathologic examination and can be difficult to interpret. OBSERVATIONS We describe a patient with nonscarring alopecia that was misdiagnosed a...

Pheomelanin is synthesized within melanocytes of hair follicles in mice of appropriate Agouti (a)or Extension (e)locus genic constitution. Alleles at the a-locus program pheomelanogenesis by altering the internal environment of hair follicles whereas alleles at the e locus do so by direct action through the genome of the melanocyte. For example, although transplanted recessive yellow (ele) mela...

Organ regenerative therapy aims to reproduce fully functional organs to replace organs that have been lost or damaged as a result of disease, injury, or aging. For the fully functional regeneration of ectodermal organs, a concept has been proposed in which a bioengineered organ is developed by reproducing the embryonic processes of organogenesis. Here, we show that a bioengineered hair follicle...

Bone morphogenetic protein (BMP) signaling is thought to perform multiple functions in the regulation of skin appendage morphogenesis and the postnatal growth of hair follicles. However, definitive genetic evidence for these roles has been lacking. Here, we show that Cre-mediated mutation of the gene encoding BMP receptor 1A in the surface epithelium and its derivatives causes arrest of tooth m...

Hair transplantation involving patients with tightly curled Afro-textured hair using follicular unit extraction (FUE) employing conventional rotary punches frequently leads to unacceptably high transection rates. These patients are unsuitable candidates for FUE hair transplantation. Transection rates were observed during FUE in a case series of 18 patients with tightly curled Afro-textured hair...

Both clinical and experimental observations show that the skin is affected by the thyroidal status. In hypothyroid patients the epidermis is thin and alopecia is common, indicating that thyroidal status might influence not only skin proliferation but also hair growth. We demonstrate here that the thyroid hormone receptors (TRs) mediate these effects of the thyroid hormones on the skin. Mice lac...

Notch signaling is involved in the cell fate determination of various cell lineages. Notch interaction with its ligand induces the cleavage of its intracellular domain (IC), and the Notch IC translocates to the nucleus and binds to RBP-J to transactivate transcription of target genes. All four Notches in mammals bind to RBP-J to exert their transactivation activities. Notch is expressed in deve...

Although the hair shaft is derived from the progeny of keratinocyte stem cells in the follicular epithelium, the growth and differentiation of follicular keratinocytes is guided by a specialized mesenchymal population, the dermal papilla (DP), that is embedded in the hair bulb. Here we show that the number of DP cells in the follicle correlates with the size and shape of the hair produced in th...

Porokeratotic eccrine and hair follicle nevus is a very rare non-hereditary disorder of keratinization with eccrine and hair follicle involvement with only 9 cases described in the literature. In 2009 the term porokeratotic anexial ostial nevus was proposed to comprehend porokeratotic eccrine and hair follicle nevus and a related and more common process without follicular involvement: porokerat...