Our patient was diagnosed with piebaldism, which is characterized by congenital hypomelanosis of the skin (leukoderma) and hair (poliosis). The condition manifests typically as a white forelock with scattered patches of depigmentation on the body. Incidence is the same in whites as in blacks. Although benign, piebaldism tends to be permanent and therefore can be socially disabling.
Piebaldism results from a mutational defect of the kit proto-oncogene, which affects the differentiation and migration of melanoblasts. The gene is inherited in an autosomal dominant pattern. Affected individuals present at birth with a relatively stable and persistent depigmentation of the hair and skin. Occasionally, repigmentation occurs spontaneously, either partially or totally. Injury often initiates the repigmentation process.
The most consistent clinical sign is the white forelock (90% of those affected). This poliosis overlies a patch of depigmented skin that is triangular or diamond-shaped, with the widest base at the frontal hairline and the points extending posteriorly to the scalp vertex and anteriorly to the nasal root. When the depigmented area overlaps the eyebrows or eyelashes, these hairs will be white also. Many patients exhibit irregularly-shaped, large vitiligolike, amelanotic patches involving the forehead, ventral and lateral chest and abdomen, mid-upper arms to wrists, and mid-thighs to mid-calves. Usually the achromic skin lesions are in a symmetric pattern.
Commonly, islands of normal or hyperpigmented skin are present within and at the border of the depigmented areas, giving the skin a spotted or thumbprint appearance.
Persons with piebaldism are generally healthy. Occasional case reports suggest a weak association with Hirschsprung disease, neurofibromatosis type I, congenital dyserythropoietic anemia type II, Diamond-Blackfan anemia, or Grover disease. Syndromes now known to be distinctly different because they do not involve kit gene mutation include Waardenburg syndrome, albinism-deafness syndrome, and Tietze syndrome.
Histology of depigmented patches reveals absent or considerably reduced numbers of melanocytes. The islands of hyperpigmentation within and at the border of the depigmented areas demonstrate normal numbers of melanocytes.
Differential diagnoses include albinism and vitiligo. While albinism is also congenital and inherited, it is characterized by partial or complete absence of melanin production of the skin, hair, and eyes. Vitiligo is usually acquired later in life and does not include the hyperpigmented macules seen at the edges of piebaldism-associated leukoderma.
As for treatment, sunscreen is needed given patients’ increased sensitivity to the sun. Affected areas can be camouflaged with makeup, hair dye, or fake tanning agents containing dihydroxyacetone. Piebaldism does not respond to any medical therapy, such as psoralens with UV light.
Surgical therapies with some success include a combination of dermabrasion and grafting of pigmented skin to the amelanotic areas. Mini-grafting as well as thin split-thickness and epidermal grafts have been proposed. In short, skin transplantation, with or without phototherapy or laser supplementation, has been reported to yield excellent repigmentation. Autologous cultured epidermal sheets offer an alternative therapy.
A family history of keloids ruled out surgery. Our patient’s parents opted to use coverup, makeups, and clothing.