Ectodermal dysplasia
Key points
- Ectodermal dysplasia is a hereditary condition characterized by abnormal development of the skin and associated structures (hair, nails and teeth, and sweat glands).
- There are many different types of ectodermal dysplasia of which X-linked anhidrotic ectodermal dysplasia is the most common.
- Cosmetic and functional improvements can be made through the use of wigs in the absence of scalp hair and dentures to replace missing and defective teeth.
- Ectodermal dysplasia is compatible with a normal life span, but constant attention must be paid to temperature regulation and other problems that may exist.
Alternative names
Anhidrotic ectodermal dysplasia
Definition
Ectodermal dysplasia is a hereditary condition characterized by abnormal development of the skin and associated structures (hair, nails and teeth, and sweat glands).
Causes, incidence, and risk factors
There are many different types of ectodermal dysplasia of which X-linked anhidrotic ectodermal dysplasia is the most common. Because the disease is X-linked, males are affected, although females in some cases may also display a range of symptoms.
An autosomal dominant form exists in which females and males are equally affected and is symptomatically almost identical to the X-linked form of the disease. Multiple genes have been discovered to cause ectodermal dysplasias.
Ectodermal dysplasia may affect, to varying degrees, all of the structures associated with the development of the skin. Absent or decreased sweating in people with anhidrotic ectodermal dysplasia is caused by absence of sweat glands.
Affected children have difficulty controlling fevers and mild illness may produce extremely high fevers, because of absent temperature regulation by sweating. Affected adults are unable to tolerate a warm environment and require special measures to maintain a normal body temperature.
Mucus membrane involvement results in chronic nasal infections with foul-smelling discharge and increased respiratory infections. Hair may be absent or very scanty. The skin is thin with light pigmentation. Teeth develop abnormally and many teeth are missing.
Symptoms
- decreased number of teeth
- peg teeth
- delayed or absent tooth formation
- inability to sweat
- absent tears (occasional)
- thin skin
- decreased pigment
- foul-smelling nasal discharge
- poor temperature regulation
- heat intolerance
- scanty hair
- absent hair
- abnormal nails
- low nasal bridge
Signs and tests
- biopsy of the mucus membranes (shows absent mucous glands, hypoplastic mucous membranes)
- biopsy of the skin (shows absent or hypoplastic sweat glands)
Written and revised by
David Cohen, M.D.
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