Hair loss and regeneration are the subjects of tremendous amount of research for multiple reasons: the well-known importance of hair in individual beauty, the fact that alopecia is a frequent dermatological disease, and that there are limited treatment options. The present work focuses on the evaluation of animal models used for hair research and regeneration. Besides mentioning the option of in vitro studies, the chapter analyzes the need of an animal model of alopecia, common used study designs, hair regrowth evaluation methods, and the limitations of the animal models in hair regrowth research. This chapter also discusses the structure of hair, its chemical composition, the properties and functions of hair, consequences of hair loss, the biology of hair loss, and regeneration and existing treatment options for alopecia. By using proper and well thought-out animal models, we aim to refine our knowledge on human hair diseases and hair regrowth. Hair research provides insights into the physiopathological pathways, genetic and cell biochemical mechanisms, and remains a field intensively explored and still inexhaustible.
Part of the book: Experimental Animal Models of Human Diseases
This chapter outlines the clinical approaches for alopecic patients that are reliable in practice. We discuss three different categories of hair evaluation options: invasive methods (biopsy), semi-invasive methods (trichogram) and noninvasive methods. Besides describing the current status of diagnosis and quantification of alopecia, the chapter provides an objective assessment of these investigation tools: detailed medical history collection by structured interview and questionnaires, clinical examination of the scalp and other hair-bearing areas, laboratory investigations, assessment of hair loss distribution (patterned/diffuse/focal), dermoscopic evaluation, assessment of alopecia severity (by pull test, hair part width, counting hair test), common scales for hair loss staging, photography of alopecic areas, biopsy, trichogram, unit area trichogram, tug test, hair mount and microscopic evaluation, electron microscopy, hair card test, hair weight determination, hair densitometry, mechanical test of hair quality and computed hair analysis. Unfortunately, the disadvantages of most of these methods generate a lack of use in clinical practice, leading to few reliable evaluation methods for patients suffering from alopecia. We underline the necessity of easy, refined and precise evaluation tools for the assessment of alopecia patients.
Part of the book: Alopecia
Psoriasis represents a chronic inflammatory skin disease with multisystemic involvement. The development of this autoimmune disorder depends on a complex interplay of genetic and environmental factors. Besides presenting the conditions associated with psoriasis, the chapter outlines the role of hormones (sex hormones, prolactin, and thyroid hormones) in psoriasis pathogenesis and evolution. The chapter indicates the clinical approaches recommended in practice: a detailed medical history collection (including prior exposure to treatments and evaluation of co-medication), a thorough physical examination (with the completion of specific severity and QoL scales), laboratory investigations and screening for malignancies (including lymphoma and skin cancer) or infection (Tuberculosis, Crohn’s disease). European Guidelines encourage the dermatologist to check for hypersensitivity, metabolic, gastro-intestinal and renal disorders, check for the need of vaccines and contraception. We discuss pre-treatment, during-treatment and post-treatment evaluation options and underline the necessity of clear evaluation steps in the assessment of psoriasis patients.
Part of the book: Tailored Treatments in Psoriatic Patients