Year : 2011 | Volume
: 3 | Issue : 3 | Page : 1--2
Part A – Hair Anatomy, Pathology, Fungal and Parasitic Infections
|How to cite this article:|
. Part A – Hair Anatomy, Pathology, Fungal and Parasitic Infections.Int J Trichol 2011;3:1-2
|How to cite this URL:|
. Part A – Hair Anatomy, Pathology, Fungal and Parasitic Infections. Int J Trichol [serial online] 2011 [cited 2020 Sep 29 ];3:1-2
Available from: http://www.ijtrichology.com/text.asp?2011/3/3/1/82146
Basic hair anatomy
Department of Dermatology, Hadassah- Hebrew University Medical Center, Jerusalem, Israel.
The human hair follicle (HF) is a sophisticated mini-organ, composed of multiple mesenchymal and epithelial cell layers, consisting of more than 20 different cell populations in total. Together with the arrector pili muscle and the sebaceous gland, the HF forms the pilosebaceous unit. It has the extraordinary capability of self-renewal, and undergoes a life-long cycle through several hair cycle phases, including the anagen (rapid growth), catagen (regression) and telogen (resting) phases. Each phase possesses its unique anatomy and structure, since the lower part of the HF is continuously remodeled in each hair cycle. In contrast, the upper segment of the HF (infundibulum and isthmus) remains permanently stable. Understanding the complex biology and function of the HF requires familiarity with its anatomy, especially of the bulge region, the putative residence of the HF stem cells, and the dermal papilla, which are believed to be responsible for the regulation of the hair cycle. Although the exact role of each part of the HF has for long been a mystery, recent advances in HF research have given us better insight on their function in maintaining HF growth and cycle. The aim of the talk is to describe the basic anatomy of the HF, while explaining the associated functions of its main segments, thus laying the foundations for better understanding of HF disease processes.
Department of Dermatology, Rambam Medical Center, and the Bruce Rappaport, Faculty of Medicine, Technion, Institute of Technology, Haifa, Israel.
In our everyday clinic, hair microscopy includes routinely processed biopsy specimens for scalp pathology and hair shaft microscopy. In children, hair shaft microscopy is often used to examine for structural abnormalities which characterize congenital hair disorders and alopecias. Scalp biopsies are occasionally obtained in children as well, because they may be useful diagnostically in both congenital and acquired alopecias. In adults, most of the hair disorders involve acquired hypotrichosis and alopecias, and scalp biopsy is the routine diagnostic approach which may be valuable in diagnosing the various subtypes of inflammatory alopecias. There are two modes of sectioning of a scalp biopsy: vertical and horizontal. The merits and flaws of each method will be discussed, and our method of complete vertical sectioning will be shown. The usefulness of scalp biopsies in acquired alopecias in both adults and children, and the utility of hair shaft microscopy will be demonstrated and discussed systematically, along with histopathological images and clinicopathologic correlations.
Tinea capitis - Review
Avner Shemer*, Boaz Amichai
Department of Dermatology, Sheva Medical Center, Tel Hashomer, Israel
Tinea capitis is a superficial fungal infectionof the scalp tinea capitis is caused by dermatophytes in the trichophyton and microsporum genera that invade the hair shaft. The clinical presentation is typically a single or multiple patches of hair loss, sometimes with a 'black dot' pattern (often with broken-off hairs), that may be accompanied by inflammation, scaling, pustules, and itching. Uncommon in adults, tinea capitis is predominantly seen in pre-pubertal children, more often in boys than girls. Over eight different species of dermatophytes are commonly associated with tinea capitis. Cases of trichophyton infection predominate from Central America to the United States and in parts of Western Europe. Infections due to microsporum species are mainly seen in South America, Southern and Central Europe, Africa and the Middle East. The disease is infectious and can be transmitted by humans, animals, or objects that harbor the fungus. Carrier states also exist where the fungus is present on the scalp but there are no clinical signs or symptoms. Treatment of tinea capitis requires usually an oral antifungal agent; griseofulvin is the most commonly used drug, but other newer antimycotic drugs, such as and fluconazole, terbinafine, itraconazole have been used successfully. In this lecture we will discuss about the dinamic distributions of the different pathogenic fungi causing tinea capitis worldwide. The role of Wood's lamp with correlation to the mycological analysis, different new azoles and the allilamins in the treatment of tinea capitis will be discussed.
Head lice and the human hair
Kosta Y. Mumcuoglu
Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Institute for Medical Research, Israel-Canada, The Hebrew University - Hadassah Medical School, Jerusalem, Israel.
The head louse (Pediculus humanus capitis) is an insect parasite, spending its entire life on human hair and feeding exclusively on blood, 4-5 times daily. Man is the only known host of this parasite. Although any part of the scalp may be colonized, lice favor the nape of the neck and the area behind the ears, where the eggs are usually laid. Hair to hair contact is by far the most common way of lice transmission. In six studies with over 4,200 children done in Israel, girls with usually long hair were 34 times more frequently infested than boys, who usually have short hair. Boys with medium length hair had more lice than those with short hair, although these differences were not significant. In girls with short hair, significantly more lice infestations were recorded than in those with long hair. Boys and girls with brown and red hair were more infested with lice than those with black and blond hair. The differences were significant for boys but not for girls. Brown-haired children were more infested with nits than those with black and blond hair. The number of children with red hair was relatively low. Pupils with straight and wavy hair were more infested than those with curly and frizzy hair. The differences were significant for girls but not for boys. Cutting the hair short or keeping girls' hair tidy decreased the chance of becoming infested. Short and straight hair is also more convenient for combing and treating with pediculicides than long and curly/frizzy hair. Wetting the hair and use of commercial shampoos and conditioners make combing with a louse comb easier and increase the chances of finding lice and eggs on the scalp.