Piebaldism is a rare hereditary pathology characterized by a violation of pigment metabolism, the appearance of a characteristic area of congenital leukoderma on the head and a white strand of hair. In children, a site of triangular depigmentation of the skin in the forehead area is determined from birth. As you get older, it increases, spreading to the area of eyelashes, eyebrows, mucous membranes. Additional white spots are formed on the front surface of the abdomen, back, chest, forearms. The diagnosis is established on the basis of clinical and anamnestic data. There is no specific treatment. Skin transplantation operations are performed to correct the external defect.
The synonymous name of piebaldism is partial or incomplete albinism. The disease refers to primary congenital hypomelanosis – pathologies with focal reduction or complete destruction of melanin due to genetic factors. Piebaldism is a rare hereditary disease, the prevalence is 1 case per 17 thousand people. Epidemiological indicators are the same among men and women, regardless of nationality and race. The first descriptions of piebaldism are found in ancient Greek medical treatises, but the search for effective treatment methods has become possible only in recent decades due to the progress of scientific knowledge about the genome and genetic mutations.
The development of the disease is due to the presence of a mutation in the KIT proto-oncogene responsible for the proliferation and migration of melanoblasts from the neural crest during intrauterine development. Inheritance of piebaldism occurs in an autosomal dominant type. This means that in order for the symptoms to manifest, the child needs to receive a defective gene from one of the parents. A genealogical thread is traced in the families of patients – the transmission of the disease from generation to generation.
The skin tone is determined by the content of coloring pigments in the dermis cells, the main of which is melanin. The intensity of its production and accumulation is influenced by two components: tyrosine, which acts as a substrate for pigment synthesis reactions, and tyrosinase, an enzyme responsible for tyrosine metabolism. With the development of piebaldism, two pathological processes are observed. The first is associated with structural changes in the enzyme, entailing failures in tyrosine metabolism, which result in a reduction in pigment production. The second process is the genetically determined inability of melanin accumulation by cells. Even during the prenatal period, a gene defect prevents the migration of melanoblasts – melanocyte progenitor cells. Other types of skin cells are not able to accumulate pigment even if there is enough of it in the body. As a result, hypopigmented areas are formed – white spots.
The classic form of the disease manifests itself from birth: newborns have a white spot on the forehead skin in the middle, resembling an inverted triangle, the top of which ends on the scalp. In the future, the area of the depigmented area increases, white (gray) hair grows on the frontal-parietal zone of the child. Piebaldism affects only the color, is unable to be the cause of atrophy or hair loss. Sometimes depigmentation covers the eyebrows and eyelashes, making them completely or partially discolored.
With age, depigmentation zones appear on other parts of the body. They have an irregular shape, more often localized at the midline of the abdomen, chest and back, on the shins, thighs and forearms. Small spots up to 1 cm in diameter can form on the mucous membranes. Hypopigmentation of the feet and hands is uncharacteristic, foci of this localization are considered as one of the key differences between piebaldism and vitiligo. An important diagnostic sign is that spots with normal or enhanced coloration may form in depigmented areas. They have different shapes and sizes, with uneven edges, are arranged unevenly, which is why the skin of patients has a peculiar “animal color”.
The disease does not affect the work of internal organs and systems, the symptoms are limited to changes in the color of the skin and hair. Uneven pigmentation often becomes a traumatic factor. Patients experience embarrassment and shame, mask stains with cosmetics, sometimes partially restrict social contacts – they do not attend informal meetings, refuse work that requires communication with people. Unusual appearance can provoke depressive disorder, the formation of isolation and insecurity. In addition, patients with piebaldism are classified as at increased risk for the development of skin cancer. They are recommended regular examinations that allow them to diagnose oncopathology at an early stage.
The examination is carried out by geneticists, dermatologists, trichologists, therapists. Diagnosis is based on anamnestic and clinical data. Specialists assess the condition of the skin, hair and mucous membranes, determine the localization and nature of depigmented areas, collect information about the presence of signs of hypomelanosis in close relatives. Differential diagnosis of piebaldism with other forms of leukoderma is performed: with infectious (leprosy, syphilitic), immune, provoked scleroderma or SLE, toxic, potentiated by exposure to various substances, environment. To clarify the diagnosis, laboratory tests are prescribed:
- Blood test. The results make it possible to exclude inflammatory and infectious processes, anemia. With piebaldism, the indicators remain normal.
- Biochemical blood testing. According to the analysis, a state of intoxication caused by improper medication intake, regular contact with harmful chemicals (harmful production) and provoking local depigmentation can be detected.
- The study of antibodies in the blood. To exclude scleroderma and systemic lupus erythematosus as causes of skin lesions, tests for antinuclear antibodies and antibodies to ribonucleins are carried out. With true piebaldism, there is no autoimmune process.
Since the cause of the disease is a genetic mutation, etiopathogenetic therapy is impossible. To eliminate the defect, an operation is performed to transplant skin flaps with preserved pigmentation on the area of hypochromatosis. To reduce the rate of development of the disease, to slow down the process of the appearance of new spots, the patient is prescribed vitamins E, PP, A and group B, preparations with copper and zinc, a diet high in buckwheat, eggs, seafood, liver. These measures increase the content of tyrosine. At the stage of scientific development, there is a treatment method based on the transplantation of melanocytes into the hypopigmentation area. Successful cell engraftment will restore the accumulation of melanin in them.
Prognosis and prevention
Piebaldism does not affect the state of physical health, a cosmetic defect can be corrected, so the quality of life of patients remains high. Despite the fact that effective treatment methods have not been developed, the disease is prognostically favorable. The hereditary nature of transmission makes prevention impossible. To prevent the progression of the disease and the development of complications, patients are recommended to have regular dermatologist reviews, limit insolation, and exclude the effects of aggressive substances on the affected areas of the skin.