Vitiligo is a chronic autoimmune disorder that causes patches of skin to lose pigment or color. The cause of vitiligo is unknown, but it may be related to immune system changes, genetic factors, stress, or sun exposure. Treatment options include topical medications, light therapy, surgery and cosmetics. The condition can show up on any skin type as a light peachy color and can appear on any place on the body in all sizes. The spots on the skin known as vitiligo are also able to “change” as spots lose and regain pigment; they will stay in relatively the same areas but can move over time and some big patches can move through the years but never disappear overnight.
Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant genetic disease that causes non-cancerous tumours to grow in the brain and on other vital organs such as the kidneys, heart, liver, eyes, lungs and skin. A combination of symptoms may include seizures, intellectual disability, developmental delay, behavioral problems, skin abnormalities, lung disease, and kidney disease.
Heterochromia is a variation in coloration most often used to describe color differences of the iris, but can also be applied to color variation of hair or skin. Heterochromia is determined by the production, delivery, and concentration of melanin. It may be inherited, or caused by genetic mosaicism, chimerism, disease, or injury. It occurs in humans and certain breeds of domesticated animals.
Waardenburg syndrome is a group of rare genetic conditions characterised by at least some degree of congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes, a white forelock or patches of light skin. These basic features constitute type 2 of the condition; in type 1, there is also a wider gap between the inner corners of the eyes called telecanthus, or dystopia canthorum. In type 3, which is rare, the arms and hands are also malformed, with permanent finger contractures or fused fingers, while in type 4, the person also has Hirschsprung's disease. There also exist at least two types that can result in central nervous system (CNS) symptoms such as developmental delay and muscle tone abnormalities.
Hypopigmentation is characterized specifically as an area of skin becoming lighter than the baseline skin color, but not completely devoid of pigment. This is not to be confused with depigmentation, which is characterized as the absence of all pigment. It is caused by melanocyte or melanin depletion, or a decrease in the amino acid tyrosine, which is used by melanocytes to make melanin. Some common genetic causes include mutations in the tyrosinase gene or OCA2 gene. As melanin pigments tend to be in the skin, eye, and hair, these are the commonly affected areas in those with hypopigmentation.
Leucism is a wide variety of conditions that result in partial loss of pigmentation in an animal—causing white, pale, or patchy coloration of the skin, hair, feathers, scales, or cuticles, but not the eyes. It is occasionally spelled leukism. Some genetic conditions that result in a "leucistic" appearance include piebaldism, Waardenburg syndrome, vitiligo, Chédiak–Higashi syndrome, flavism, isabellinism, xanthochromism, axanthism, amelanism, and melanophilin mutations. Pale patches of skin, feathers, or fur can also result from injury.
Albinism-black lock-cell migration disorder is the initialism for the following terms and concepts that describe a condition affecting a person's physical appearance and physiology: (1) A – albinism, (2) B – black lock of hair, (3) C – cell migration disorder of the neurocytes of the gut, and (4) D – sensorineural deafness. The syndrome is caused by mutation in the endothelin B receptor gene (EDNRB).
Phakomatoses, also known as neurocutaneous syndromes, are a group of multisystemic diseases that most prominently affect structures primarily derived from the ectoderm such as the central nervous system, skin and eyes. The majority of phakomatoses are single-gene disorders that may be inherited in an autosomal dominant, autosomal recessive or X-linked pattern. Presentations may vary dramatically between patients with the same particular syndrome due to mosaicism, variable expressivity, and penetrance.
Piebaldism refers to the absence of mature melanin-forming cells (melanocytes) in certain areas of the skin and hair. It is a rare autosomal dominant disorder of melanocyte development. Common characteristics include a congenital white forelock, scattered normal pigmented and hypopigmented macules and a triangular shaped depigmented patch on the forehead. There is nevertheless great variation in the degree and pattern of presentation, even within affected families. In some cases, piebaldism occurs together with severe developmental problems, as in Waardenburg syndrome and Hirschsprung's disease.
Greying of hair, also known as greying, canities, or achromotrichia, is the progressive loss of pigmentation in the hair, eventually turning the hair grey or white which typically occurs naturally as people age.
Amelanism is a pigmentation abnormality characterized by the lack of pigments called melanins, commonly associated with a genetic loss of tyrosinase function. Amelanism can affect fish, amphibians, reptiles, birds, and mammals including humans. The appearance of an amelanistic animal depends on the remaining non-melanin pigments. The opposite of amelanism is melanism, a higher percentage of melanin.
Postinflammatory hypopigmentation is a cutaneous condition characterized by decreased pigment in the skin following inflammation of the skin.
X-linked reticulate pigmentary disorder is a rare X-linked genetic condition in which males manifest multiple systemic symptoms and a reticulated mottled brown pigmentation of the skin, which, on biopsy, demonstrated dermal deposits of amyloid. Females usually only have linear streaks of hyperpigmentation.
Nevus depigmentosus is a loss of pigment in the skin which can be easily differentiated from vitiligo. Although age factor has not much involvement in the nevus depigmentosus but in about 19% of the cases these are noted at birth. Their size may however grow in proportion to growth of the body. The distribution is also fairly stable and are nonprogressive hypopigmented patches. The exact cause of nevus depigmentosus is still not clearly understood. A sporadic defect in the embryonic development has been suggested to be a causative factor. It has been described as "localised albinism", though this is incorrect.
Vogt–Koyanagi–Harada disease (VKH) is a multisystem disease of presumed autoimmune cause that affects melanin-pigmented tissues. The most significant manifestation is bilateral, diffuse uveitis, which affects the eyes. VKH may variably also involve the inner ear, with effects on hearing, the skin, and the meninges of the central nervous system.
Autoimmune skin diseases occur when the immune system of an infected animal attacks its own skin. In dogs, autoimmune skin diseases are usually not detected until visible symptoms appear, which differs from detection in humans who are able to verbally express their concerns. Genetics, nutrition, and external environmental factors all collectively contribute to increasing the probability an autoimmune skin disease occurring. The severity of symptoms varies based on the specific disease present and how far it has progressed. Diagnosis often requires the onset of visible symptoms and for a biopsy to be performed. For many diseases, the condition itself cannot be cured, but a veterinarian can prescribe medications and other forms of treatment to help manage the symptoms of the dog.
Waardenburg syndrome type 1 is a congenital disorder that caused by a mutation in the PAX3 gene that results in abnormal development in the neural crest during early development. Type 1 results in early graying and white forelock and a notable distance between the eyes, noted as dystopia canthorum. Common symptoms of the disease also includes non-progressive hearing loss in majority of patients with type 1. Patients can display complete or partial heterochromia and hypoplastic blue irides and congenital leukemia.
Waardenburg syndrome type 4A is an extremely rare congenital disorder caused by a mutation in an endothelin receptor gene. It results in common Waardenburg syndrome symptoms such as abnormal hair and skin pigmentation and heterochromia, but also present with symptoms of Hirschsprung's disease. Symptoms include abdominal pain and bowel obstruction. Waardenburg syndrome type 4A is the rarest among the types, appearing only once in about every 1,000,000 individuals. There have only been a total of 50 cases reported in total as of 2016.
Desmond John Tobin is an Irish academic, researcher and author. He is a full professor of dermatological science at University College Dublin and the director of the Charles Institute of Dermatology. He was chair of British Society for Investigative Dermatology from 2018 to 2020. Tobin is a fellow of The Royal College of Pathologists, of the Higher Education Academy, of the Royal Society of Biology, Institute of Biomedical Science, and of the Institute of Trichologists.
