HED is an X-linked recessive disease involving abnormalities of tissues of ectodermal origin due to developmental disturbances in the embryonal state. These abnormalities include 1) trichodysplasia, 2) dental defects, 3) onychodysplasia, and 4) dyshidrosis. Also common are thin, dry skin, typical facial features such as saddle-nose deformity and periorbital wrinkling/pigmentation, otolaryngologic problems, eczema, and respiratory disease. Diagnosis of HED may be suspected in a child with recurrent fever of unknown etiology, thin blond hair, and anodontia. The diagnosis can be strengthened by low or absent sweat pore counts, and confirmed by palmar skin biopsy. Management is multidisciplinary and mainly involves avoidance of hyperpyrexia in the early years. At school age and beyond, the cosmetic features become more of a concern to the patient. As adults, these patients usually lead fairly normal lives both physically and socially, and have a life expectancy similar to that of the general population.