The inability to sweat: what is ectodermal dysplasia?

Ectodermal dysplasias are a rare group of genetic disorders used to describe a group of conditions involving the skin, teeth, hair, nails, and sweat/mucous glands.  Multiple syndromes can be associated with ectodermal dysplasias, ranging from mild to severe. These conditions typically occur during fetal development.

The most common forms of ectodermal dysplasias are known as hypohidrotic/anhydrotic ectodermal dysplasia, meaning children affected with this condition have few to no sweat glands. The syndromes associated with this type of ectodermal dysplasias are often derived from the mother’s X-chromosome and typically affect males more than females. If both parents have a recessive gene, the parents may not be affected but have a child with this condition.

These syndromes may include:

• Sparse, fine hair on the head, eyebrows, and lashes
• Missing or cone-shaped teeth
• Typical facial features including protuberant forehead, flattened nasal bridge, thick lips, and wrinkled skin around the eyes
• Dry, thin, finely wrinkled skin
• Decreased or absent sweat glands which leads to reduced ability to sweat
• Abnormal mucous glands which can predispose a person to frequent respiratory infections, diarrhea, and feeding problems
• Heat intolerance

The most worrisome complication of hypohydrotic/anhydrotic ectodermal dysplasias is the inability to sweat. If a child becomes overheated or develops a fever, this can lead to an extreme rise in body temperature. It is very important for parents of these children to recognize the early warning signs of overheating and take prompt measures to cool their child. Absent sweat glands can be diagnosed by a skin biopsy, often done on the palm of the hand.

Another less common type of ectodermal dysplasia is hidrotic, meaning the children have normal sweat glands. This type is associated with nail and hair abnormalities, as well as darkening of the skin over elbows, knees, and knuckles.

Because they are due to a genetic defect, ectodermal dysplasias cannot be cured. Some children may require dentures at an early age. Others may benefit from wearing a wig if the hair thinning and loss is severe. Genetic counseling may also benefit parents who want to have other children in the future.

Reviewed by Dr. Sara Connolly, March 2019