Technical Abstract: The ectodermal dysplasia (ED) syndromes are a group of inherited disorders that affect the ectodermal-derived tissues of the body. The hypohidrotic (HED) form is characterized by a triad of clinical features including hypohidrosis, anomalous dentition, and hypotricosis. The diagnosis of ED syndromes should be suspected on the basis of clinical and dental examination. Children with HED are at risk for heat-related illness and must be protected from exposure to increased ambient temperatures.