Sweat testing using a modified version of the method described by Minor was performed in 5 children affected with hypomelanosis of Ito. In 4 cases the areas of hypopigmentation were arranged in patterns following the lines of Blaschko, whereas in one case a phylloid pattern was observed. In 4 cases the hypomelanotic areas were shown to be anhidrotic. In one case of hypomelanosis following Blaschko's lines, sweat testing was normal and did not reveal any functional difference between the normally pigmented and the hypopigmented areas. These results provide a clinical illustration of the fact that hypomelanosis of Ito is not an entity but constitutes a cutaneous manifestation of various states of mosaicism.

Abnormalities, Multiple↗

PubMedDate not supplied

The different faces of pili bifurcati. A review.

Pili bifurcati is an uncommon hair shaft dysplasia characterized by bifurcation of the hair shaft. The two characteristics that define the dysplasia are: 1. Each bifurcation produces two separate parallel branches which fuse again to form a single shaft. 2. Each branch of the successive bifurcations is covered with its own cuticle. Currently, there is confusion between the terms "pili bifurcati" and "pili gemini". The name "pili gemini" is used to define a kinetic papilla that splits at the upper end from single to double-tipped during the anagen phase and consequently the same follicular matrix produces two different-sized hair shafts having separate cuticles that emerge through a single pilary canal. Pili gemini maintains the double tipped papilla and consequently the hair shaft does not fuse again. Papillar tips that divide into several tips will produce several hair shafts, that characteristically do not fuse again. When the same papilla changes its shape repeatedly during the anagen phase, it can produce hair shafts with bifurcations at irregular intervals: pili multibifurcati. And, as it is also possible for one of the new papillae to split again in two, the hair shaft may be doubly bifurcated: pili bi, bifurcati. Pili bifurcati should be distinguished from acquired splitting of hair shafts that do not represent true bifurcations because the two split parts are never surrounded by a complete cuticle. Such acquired splitting may be called "central trichoptilosis".

Hair↗

PubMedDate not supplied

Current understanding of androgenetic alopecia. Part II: clinical aspects and treatment.

The first signs of androgenetic alopecia (AGA) may start to develop with the onset of puberty. The prevalence of progressive AGA approaches 50% of Caucasian men and women beyond the age of 40; whereas in Asian, native American and African-American men the prevalence is lower and AGA is less severe. Only exceptionally laboratory tests or scalp biopsies are needed to confirm the diagnosis. Therefore the clinical assessment of AGA is largely a matter of common sense and practice. The loss of hair is often trivialised, but hair loss may have profound effects on a patient's well-being and quality of life. The treatment of AGA is obscured by myths. Many products or procedures are advertized for the treatment of AGA such as vitamins, trace elements, exotic herbs, amino acids, "soft laser", scalp massage, etc. Most of these techniques or substances have never been verified in sound clinical trials. Because of the psychosocial impact of hair loss, however, it is important to explain to patients what they may expect in terms of continuing hair loss, and that response to any therapy may be slow and may include hair regrowth or only retardation of further thinning. The aim of AGA treatment is to reverse or to stabilize the process of HF miniaturization and with this overview we summarize the present treatment modalities for both men and women.

5-alpha Reductase Inhibitors↗

PubMedDate not supplied

Phylloid hypomelanosis is closely related to mosaic trisomy 13.

Phylloid hypomelanosis is a distinct type of pigmentary mosaicism characterized by congenital hypochromic macules resembling a floral ornament with various elements such as round or oval patches, macules resembling the asymmetrical leaves of a begonia, or oblong lesions. A review of cases with documentation of cytogenetic findings showed that aberrations involving chromosome 13 were present in 5 out of 6 patients. Examination of blood lymphocytes revealed a 46, XX/47 XX, +13 or 46, XX/47, XX, +der (13) mosaic in three of these cases and a karyotype 46, XX, t(13;13) in the other two cases. Cytogenetic analysis of skin fibroblasts showed chromosomal mosaicism in 4 of the 5 patients. In the remaining case, a chromosome 13 translocated on 13 was found in 100% of blood lymphocytes and skin fibroblasts, suggesting that mosaicism involving chromosome 13 may have developed in the melanocyte system. In conclusion, contrasting with hypomelanosis of Ito which is a cutaneous sign of many different states of mosaicism, phylloid hypomelanosis seems to originate preponderantly from a mosaic state involving chromosome 13. Future case reports may help to delineate further the significance of this relationship.

Adolescent↗

PubMedDate not supplied

Genetic susceptibility and severity of alopecia areata in human and animal models.

Alopecia areata (AA) is a non-scarring, inflammatory form of hair loss. Human and animal model observations suggest that AA is an autoimmune mediated disease. Genetic influence has been clearly demonstrated in many other autoimmune diseases and one would expect that AA is no exception. AA in rodent models involves genetic susceptibility and it is possible to cross breed the AA phenotype to unrelated rodent strains. Segregation analysis of rodent breeding programs suggests the involvement of several dominant and secondary genes. The increased frequency of AA in genetically related individuals, suggests that human AA expression also involves genetic susceptibility. Within the general population, AA does not segregate as a Mendelian, monogenic trait. AA is a continuous trait with varying degrees of hair loss within the affected population. This suggests that human AA expression involves a complex interaction of multiple genes. AA is most likely a polygenic disease where several, potentially identifiable, major genes affect disease susceptibility and minor severity modifying genes may further affect the phenotype. Here we review the literature on humans and animal models for AA to identify data in support of AA as a polygenic, multivariate penetrance disease with a threshold level for disease onset. Genome wide allelic association screening of animal models and genetically related human sibling pairs may be a suitable approach to identifying susceptibility and severity modifying genes for AA.

Alopecia Areata↗