X-Linked Hypohidrotic Ectodermal Dysplasia: Clinical Features

Knowledge about ectodermal dysplasias, particularly about the hypohidrotic type, has evolved significantly over time. The first description of men without teeth or hair was made by Danz at the end of the eighteenth century. There followed descriptions of isolated and familial cases of what is now called X-linked hypohidrotic ectodermal dysplasia (XLHED), formerly known by the eponym Christ-Siemens-Touraine syndrome. This is the most common and best-known ectodermal dysplasia and mainly affects hemizygous males. The cardinal signs of XLHED are hypohidrosis causing hyperthermia, hypotrichosis, and morphological and numerical changes to teeth. These and other clinical features, such as alterations in the skin, nails, eyes, ears, nose, throat, and glands, are discussed in this chapter. The text deals with the main manifestations of the disorder, which are observed in most affected individuals, including glandular alterations with clinical repercussions, as is the case of Meibomian glands. Manifestations in heterozygous females are briefly discussed. The main therapeutic measures indicated to patients are also briefly discussed, with the recommendation of follow-up by a multidisciplinary team that comprises a pediatrician, dermatologist, otorhinolaryngologist, dentist, nutritionist, speech therapist, psychologist, and geneticist.