Ectodermal dysplasia is not a single disorder, but a group of closely related conditions. More than 150 different syndromes have been identified.
Ectodermal dysplasias are described as "heritable conditions in which there are abnormalities of two or more ectodermal structures such as the hair, teeth, nails, sweat glands, cranial-facial structure, digits and other parts of the body." 
Individuals affected by an ED syndrome frequently have abnormalities of the hair follicles. Scalp and body hair may be thin, sparse, and very light in color, even though beard growth in affected males may be normal. The hair may be excessively brittle, curly, or even twisted. Wigs and make-up can mask defects in hair development.
Fingernails and toenails may be thick, abnormally shaped, discolored, ridged, slow-growing, or brittle. The cuticles may be prone to infections.
The skin may be lightly pigmented. In some cases, red or brown pigmentation may be present. Skin can be prone to rashes or infections and can be thick over the palms and soles. Care must be taken to prevent cracking, bleeding, and infection.
Many individuals affected by ED syndromes cannot perspire. Their sweat glands may function abnormally or may not have developed at all. Without normal sweat production, the body cannot regulate temperature properly. Therefore, overheating is a common problem, especially during hot weather. Access to cool environments is important.
Abnormalities in the development of tooth buds usually result in missing teeth or in the growth of teeth that are peg-shaped or pointed. The enamel may also be defective. Dental treatment almost always is necessary and children may need dentures as early as two years of age. Multiple denture replacements are often needed as the child grows, and dental implants may be an option in adolescence. In other cases, teeth can be crowned. Orthodontic treatment also may be necessary. Because dental treatment is complex, a multi-disciplinary approach is best.
In some types of ED, abnormal development of parts of the eye can result in dryness of the eye, cataracts, and vision defects. Professional eye care can help minimize the effects of ED on vision. Similarly, abnormalities in the development of the ear may cause hearing problems. Respiratory infections can be more common because the normal protective secretions of the mouth and nose are not present. Precautions must be taken to limit infections.
Template:Congenital malformations and deformations of integument da:Ektodermale dysplasier de:Ektodermale Dysplasie nl:Ectodermale dysplasie