Pigmentation disorder

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Pigmentation disorder
Specialty Dermatology

Pigmentation disorders are disturbances of human skin color. [1] There may be a loss or reduction, which may be related to loss of melanocytes or the inability of melanocytes to produce melanin or transport melanosomes correctly. [1]

Contents

Most pigmentation disorders involve the underproduction or overproduction of melanin. [2] [3]

Causes

Skin pigmentation is a frequent disorder that has a number of potential causes. Genetics, sun exposure, and some drugs are the three main factors that contribute to skin pigmentation. [4]

The most frequent cause of low melanin concentration (hypopigmentation) is prior skin trauma, which includes skin lesions including blisters, burns, infections, exposure to chemicals, and other wounds. The skin will appear paler than the surrounding skin surface once an injury has healed. [4]

Different areas of the skin may be hypopigmented as a result of other genetic illnesses. Hypopigmentation can be caused by hereditary conditions such as vitiligo, melasma, pityriasis versicolor, pityriasis alba, albinism, and fungal infections. [4]

Hyperpigmentation results from an increase in melanin synthesis, which is mostly brought on by sun exposure, dermatological disorders, hormones, aging, genetic factors, skin injuries or inflammation, and acne. Sun exposure, which greatly increases the synthesis of melanin, is the most common cause of hyperpigmentation. [4]

Mechanism

Genetics is one of the most common causes of skin color. Skin cells called melanocytes are responsible for producing melanin. The number of melanocytes that each person will have may be predicted by genetics. Melanosomes, which are organelles containing melanin, must be transported and increased during hyperpigmentation and tanning, while they shrink during hypopigmentation. [4]

Skin pigmentation is frequently caused by sun exposure. To protect itself against UV radiation from the sun, the body makes more melanin. As a result, the skin may become more pigmented to protect it from the sun's rays. [4]

The pigmentation of the skin may also be lightened by certain drugs. Antibiotics are one type of medications that can increase the synthesis of melanin, which darkens skin. Skin pigmentation may also become more intense when certain drugs, such birth control pills, are taken concurrently. [4]

Related Research Articles

<span class="mw-page-title-main">Albinism in humans</span> Condition characterized by absence of pigment

Albinism is a congenital condition characterized in humans by the partial or complete absence of pigment in the skin, hair and eyes. Albinism is associated with a number of vision defects, such as photophobia, nystagmus, and amblyopia. Lack of skin pigmentation makes for more susceptibility to sunburn and skin cancers. In rare cases such as Chédiak–Higashi syndrome, albinism may be associated with deficiencies in the transportation of melanin granules. This also affects essential granules present in immune cells, leading to increased susceptibility to infection.

<span class="mw-page-title-main">Human skin color</span>

Human skin color ranges from the darkest brown to the lightest hues. Differences in skin color among individuals is caused by variation in pigmentation, which is the result of genetics, exposure to the sun, disorders, or some combination thereof. Differences across populations evolved through natural selection or sexual selection, because of social norms and differences in environment, as well as regulations of the biochemical effects of ultraviolet radiation penetrating the skin.

<span class="mw-page-title-main">Melanin</span> Group of natural pigments found in most organisms

Melanin is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes.

<span class="mw-page-title-main">Melanocyte</span> Melanin-producing cells of the skin

Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer of the skin's epidermis, the middle layer of the eye, the inner ear, vaginal epithelium, meninges, bones, and heart found in many mammals and birds. Melanin is a dark pigment primarily responsible for skin color. Once synthesized, melanin is contained in special organelles called melanosomes which can be transported to nearby keratinocytes to induce pigmentation. Thus darker skin tones have more melanosomes present than lighter skin tones. Functionally, melanin serves as protection against UV radiation. Melanocytes also have a role in the immune system.

<span class="mw-page-title-main">Freckle</span> Melanin spots on skin

Freckles are clusters of concentrated melaninized cells which are most easily visible on people with a fair complexion. Freckles do not have an increased number of the melanin-producing cells, or melanocytes, but instead have melanocytes that overproduce melanin granules (melanosomes) changing the coloration of the outer skin cells (keratinocytes). As such, freckles are different from lentigines and moles, which are caused by accumulation of melanocytes in a small area. Freckles can appear on all types of skin tones. Of the six Fitzpatrick skin types, they are most common on skin tones 1 and 2, which usually belong to North Europeans. However, it can also be found on people all over the world. In England a historical term for freckles is summer-voys, sometimes spelt summervoise, which may be related to the German term Sommersprossen.

The melanocyte-stimulating hormones, known collectively as MSH, also known as melanotropins or intermedins, are a family of peptide hormones and neuropeptides consisting of α-melanocyte-stimulating hormone (α-MSH), β-melanocyte-stimulating hormone (β-MSH), and γ-melanocyte-stimulating hormone (γ-MSH) that are produced by cells in the pars intermedia of the anterior lobe of the pituitary gland.

<span class="mw-page-title-main">Hyperpigmentation</span> Darkening of an area of skin or nails due to increased melanin

Hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin.

<span class="mw-page-title-main">Hypopigmentation</span> Area of skin becoming lighter than the baseline skin color

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.

<span class="mw-page-title-main">Melasma</span> Medical condition

Melasma is a tan or dark skin discoloration. Melasma is thought to be caused by sun exposure, genetic predisposition, hormone changes, and skin irritation. Although it can affect anyone, it is particularly common in women, especially pregnant women and those who are taking oral or patch contraceptives or hormone replacement therapy medications.

<span class="mw-page-title-main">Tyrosinase</span> Enzyme for controlling the production of melanin

Tyrosinase is an oxidase that is the rate-limiting enzyme for controlling the production of melanin. The enzyme is mainly involved in two distinct reactions of melanin synthesis otherwise known as the Raper–Mason pathway. Firstly, the hydroxylation of a monophenol and secondly, the conversion of an o-diphenol to the corresponding o-quinone. o-Quinone undergoes several reactions to eventually form melanin. Tyrosinase is a copper-containing enzyme present in plant and animal tissues that catalyzes the production of melanin and other pigments from tyrosine by oxidation. It is found inside melanosomes which are synthesized in the skin melanocytes. In humans, the tyrosinase enzyme is encoded by the TYR gene.

<span class="mw-page-title-main">Skin whitening</span> Practice of using chemical substances to lighten the skin

Skin whitening, also known as skin lightening and skin bleaching, is the practice of using chemical substances in an attempt to lighten the skin or provide an even skin color by reducing the melanin concentration in the skin. Several chemicals have been shown to be effective in skin whitening, while some have proven to be toxic or have questionable safety profiles. This includes mercury compounds which may cause neurological problems and kidney problems.

<span class="mw-page-title-main">Griscelli syndrome</span> Medical condition

Griscelli syndrome is a rare autosomal recessive disorder characterized by albinism (hypopigmentation) with immunodeficiency, that usually causes death by early childhood. Researchers have developed three different classifications of the form of disorder, characterised by different signs and symptoms. Type 1 Griscelli syndrome is associated with severe brain function issues along with distinctive discolouring of the hair and skin. Type 2 Griscelli syndrome have immune system abnormalities in addition to hypopigmentation of skin and hair. Finally, type 3 is seen as those only affected by hypopigmentation of the skin and hair. This type is not associated with immune deficiencies or neurological abnormalities.

<span class="mw-page-title-main">Piebaldism</span> Medical condition

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.

<span class="mw-page-title-main">Smoker's melanosis</span> Medical condition

Smoker's melanosis is seen with the naked eye as a brown to black pigmentation of the oral tissue i.e. the gums, cheeks or palate as well as in larynx. It is most often seen in the lower labial gingiva of tobacco users. Most easily it is found in Caucasians, due to their lack of a genetically caused melanin pigmentation.

Oculocutaneous albinism type I or type 1A is form of the autosomal recessive condition oculocutaneous albinism that is caused by a dysfunction in the gene for tyrosinase.

<span class="mw-page-title-main">Ocular albinism type 1</span> Most common type of ocular albinism

Ocular albinism type 1(OA1) is the most common type of ocular albinism, with a prevalence rate of 1:50,000. It is an inheritable classical Mendelian type X-linked recessive disorder wherein the retinal pigment epithelium lacks pigment while hair and skin appear normal. Since it is usually an X-linked disorder, it occurs mostly in males, while females are carriers unless they are homozygous. About 60 missense and nonsense mutations, insertions, and deletions have been identified in Oa1. Mutations in OA1 have been linked to defective glycosylation and thus improper intracellular transportation.

Melanonychia is a black or brown pigmentation of a nail, and may be present as a normal finding on many digits in Afro-Caribbeans, as a result of trauma, systemic disease, or medications, or as a postinflammatory event from such localized events as lichen planus or fixed drug eruption.

Postinflammatory hypopigmentation is a cutaneous condition characterized by decreased pigment in the skin following inflammation of the skin.

Oral pigmentation is asymptomatic and does not usually cause any alteration to the texture or thickness of the affected area. The colour can be uniform or speckled and can appear solitary or as multiple lesions. Depending on the site, depth, and quantity of pigment, the appearance can vary considerably.

<span class="mw-page-title-main">Dark skin</span> Human skin color

Dark skin is a type of human skin color that is rich in melanin pigments. People with dark skin are often referred to as black people, although this usage can be ambiguous in some countries where it is also used to specifically refer to different ethnic groups or populations.

References

  1. 1 2 James, William D.; Elston, Dirk; Treat, James R.; Rosenbach, Misha A.; Neuhaus, Isaac (2020). "36. Disturbances of pigmentation". Andrews' Diseases of the Skin: Clinical Dermatology (13th ed.). Edinburgh: Elsevier. pp. 862–880. ISBN   978-0-323-54753-6.
  2. "MedlinePlus: Skin Pigmentation Disorders".
  3. "Introduction: Pigment Disorders: Merck Manual Home Edition".
  4. 1 2 3 4 5 6 7 Thawabteh, Amin Mahmood; Jibreen, Alaa; Karaman, Donia; Thawabteh, Alà; Karaman, Rafik (2023-06-18). "Skin Pigmentation Types, Causes and Treatment—A Review". Molecules. 28 (12). MDPI AG: 4839. doi: 10.3390/molecules28124839 . ISSN   1420-3049. PMC   10304091 .

Further reading