What is piebaldism

Piebaldism is an uncommon inherited pigmentation disorder manifesting at birth with patchy leukoderma (white skin) and white hair (poliosis). Consequently, the most prominent trait of piebaldism is a white forelock (a patch of white hair immediately above the hairline). Piebaldism is an autosomal dominant genetic condition, so each offspring of an affected parent has a 50% chance of inheriting the disorder.

Epidemiology of piebaldism

The incidence of piebaldism is unknown but is estimated to range between 1:40,000 and 1:100,000. Both genders are affected equally. There is no difference in prevalence between ethnic groups, but the disorder is more noticeable and readily identifiable in people with darker skin tones.

Causes of piebaldism

75% of cases of piebaldism are due to mutations of the KIT proto-oncogene on chromosome 4; over 45 distinct point mutations, deletions, nucleotide splice mutations, and insertions of the KIT gene have been identified. The KIT gene mutation causes abnormal migration of melanoblasts from the embryonic neural crest to the epidermis, resulting in melanocyte-deficient skin patches.

Clinical features of piebaldism

White forelock, leukoderma of the central portion of the forehead, eyebrow and eyelash hair may also be affected, white patches of face, trunk, and extremities, and a narrow border of hyperpigmented skin surround the white unpigmented patches are the clinical characteristics of piebaldism. In the mild form, only small patches of leukoderma may be present, whereas in the severe form, the forelock is white and there are larger white patches on the trunk and extremities.

Diagnosis of piebaldism

Piebaldism is clinically diagnosed at birth or shortly thereafter. A leukoderma skin biopsy specimen will reveal the absence of melanocytes and melanin pigment. The diagnosis can be confirmed by genetic testing of a peripheral blood sample.

Management of piebaldism

The treatment begins with sun protection measures, solar avoidance during peak UV exposure hours, and self-examination of the skin to detect skin cancer. The surgical and procedural treatment consists of dermabrasion followed by melanocyte-enriched cell suspensions, melanocyte transplant, suction epidermal grafting, or full-thickness punch grafting. There may be a need for a combination of these methods, which can be enhanced by UV light therapy. Cosmetic camouflage techniques can conceal hair and skin pigmentation changes.

Complications of piebaldism

The complications of piebaldism include sunburn, skin cancers, and psychosocial consequences.

Written by

Mohammed Alahmadi, Medical Student.

References

DermNet

UpToDate