PIEBALDISM

The name piebaldism is derived from a combination of the “pie” in the magpie (a bird of black and white plumage) and the “bald” of the bald eagle (the US national bird that has a white feathered head). Hence the major characteristic of piebaldism is a white forelock (a patch of white hair directly above the forehead).

What is piebaldism?

Piebaldism is a rare inherited condition characterised by:

White forelock in 80-90% of those affected (poliosis)
White patch (due to absence of pigmentation) of the central portion of the forehead
Eyebrow and eyelash hair may also be affected, either continuously or discontinuously with the forelock
White patches of skin may also be seen on the face (particularly the chin), trunk and extremities (hands and feet are not usually affected)
Often a narrow border of hyperpigmented skin surrounds the white unpigmented patches
Sometimes islands of normal or hyperpigmented skin occur within the white patches
The condition is present at birth and usually remains unchanged throughout life.

What is the cause of piebaldism?

Piebaldism is due to an absence of melanocytes in affected skin and hair follicles. This is caused by mutations of the KIT proto-oncogene. 14 point mutations, 9 deletions, 2 nucleotide splice mutations, and 3 insertions of the KIT gene are believed to be mutations causing piebaldism. The severity of the condition correlates with the site of the mutation within the KIT gene.

Piebaldism is an autosomal dominant genetic disorder meaning half of an affected person's children will also have the condition.

Piebaldism is one of the cutaneous signs of Waardenburg syndrome.

How is the diagnosis made?

Skin biopsy from patients with piebaldism demonstrates complete lack of melanocytes and melanin pigment. In vitiligo, lesions appear later in life and their configuration and distribution is quite different. If deafness is apparent and the distance between the eyes is greater than normal then the diagnosis of Waardenburg syndrome needs to be considered.

What is the treatment for piebaldism?

Piebaldism is a benign disorder. However, patients with the condition are at risk of sunburn and other disorders caused by overexposure to the sun. Patients must be educated about use of sunscreens, sun protective measures, and sun avoidance during peak hours of UV exposure, and self examination of the skin to detect any sun damage that may increase the risk of skin cancer.

Patients who are self-conscious about their appearance may benefit from the following treatments:

Dermabrasion of areas of depigmentation followed by the application of melanocyte-enriched cell suspensions
Melanocyte transplant by shaving off the top layer of skin (epidermis) and replacing it by shaved-off skin from another site
Suction epidermal grafting or full-thickness punch grafts
A combination of these methods may be required and can be augmented by the addition of UV light therapy.
 
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