Introduction The diagnosis and management of skin diseases in the anogenital region may be complex. The juxtaposition of urinary, genital and alimentary tracts gives rise to special considerations at this site ( Fig. 73.1 ), and disease of any of…
Introduction From both a clinical and histologic standpoint, the oral cavity is an amazingly diverse anatomic region. This is not surprising when one considers the various tasks and environmental interactions that take place within the mouth. Sites that are associated…
Anatomy Key features ▪ Nail matrix → nail plate production proximal matrix → dorsal nail plate distal matrix (lunula) → ventral nail plate ▪ Proximal nail fold → nail matrix protection ▪ Nail bed and hyponychium → nail plate adhesion…
Key features ▪ Hypertrichosis refers to excessive growth of hair anywhere on the body, whereas hirsutism represents excessive hair growth within androgen-dependent sites in girls and women ▪ Hypertrichosis may be generalized or localized, with etiologies ranging from genodermatoses to…
Introduction In this chapter, the major non-cicatricial (non-permanent) alopecias will be reviewed first, followed by a discussion of cicatricial alopecias and a review of structural hair shaft abnormalities. Chapter 68 reviews the structure and function of the hair follicle as…
Key features ▪ The pilosebaceous unit and nail apparatus are epidermal derivatives that produce two of the hardest epithelial structures in mammalian biology ▪ The hair follicle is the only continuously cycling organ in mammals, while the nail exhibits uninterrupted…
Skin color depends upon the amount and distribution of melanin and other pigments such as hemoglobin, which can influence light absorption, reflection, and scattering. Disorders of hyperpigmentation usually result from an increase in melanin production and, on occasion, from an…
Key features ▪ Leukoderma and hypopigmentation refer to lightening of the skin, which is classically due to decreased epidermal melanin (hypomelanosis) ▪ Melanocytopenic hypomelanosis, characterized by a reduction in the number of melanocytes, can result from a variety of defects…
Key features ▪ The major determinant of normal skin color is the activity of melanocytes, i.e. the quantity and quality of pigment production, not the density of melanocytes ▪ Melanocytes contain a unique intracytoplasmic organelle, the melanosome, which is the…
Key features ▪ The human neural tube is thought to close in an intermittent, multisite pattern, and neural tube defects that present as midline cutaneous lesions (e.g. cephaloceles, heterotopic brain tissue, rudimentary meningoceles) typically occur at the junction between two…