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unusual darkening of the skin

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/06/01 22:52:02」(JST)

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

Causes

Hyperpigmentation can be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris.^[1] People with darker Asian, Mediterranean, or African skin tones are more prone to hyperpigmentation, especially with excess sun exposure.

Many forms of hyperpigmentation are caused by an excess production of melanin. Hyperpigmentation can be diffuse or focal, affecting such areas as the face and the back of the hands. Melanin is produced by melanocytes at the lower layer of the epidermis. Melanin is a class of pigment responsible for producing color in the body in places such as the eyes, skin, and hair. As the body ages, melanocyte distribution becomes less diffuse and its regulation less controlled by the body. UV light stimulates melanocyte activity, and where concentration of the cells is greater, hyperpigmentation occurs. Another form of hyperpigmentation is post inflammatory hyperpigmentation. These are dark and discolored spots that appear on the skin following acne that has healed.^[2]

Hyperpigmentation is associated with a number of diseases or conditions, including the following:

Addison's disease and other sources of adrenal insufficiency, in which hormones that stimulate melanin synthesis, such as melanocyte-stimulating hormone (MSH), are frequently elevated.
Cushing's disease or other excessive adrenocorticotropic hormone (ACTH) production, because MSH production is a byproduct of ACTH synthesis from proopiomelanocortin (POMC).
Acanthosis nigricans – hyperpigmentation of intertriginous areas associated with insulin resistance.
Melasma, also known as chloasma – patchy hyperpigmentation often found in pregnant women.
Linea nigra – a hyperpigmented line found on the abdomen during pregnancy.
Peutz-Jeghers syndrome – an autosomal dominant disorder characterized by hyperpigmented macules on the lips and oral mucosa and gastrointestinal polyps.
Exposure to certain chemicals such as salicylic acid, bleomycin, and cisplatin.
Smoker's melanosis
Celiac disease
Cronkite-Canada syndrome
Porphyria
Tinea fungal infections such as ringworm
Haemochromatosis - a common but debilitating genetic disorder characterized by the chronic accumulation of iron in the body.
Mercury poisoning - particularly cases of cutaneous exposure resulting from the topical application of mercurial ointments or skin-whitening creams.
Aromatase deficiency
Nelson's syndrome
Grave's disease
As a result of tinea cruris.

Hyperpigmentation can sometimes be induced by dermatological laser procedures.

Treatment

Treatment of hyperpigmentation may include hydroquinone, kojic acid, alpha hydroxy acids, azelaic acid, ascorbic acid, tretinoin (Retinol), topical glucocorticoids, and licorice extract. Sunscreen may help to prevent these dark spots.^{[citation needed]}

References

^ "Hyperpigmentation". Dermatalogic Disease Database. American Osteopathic College of Dermatology. Retrieved 2006-03-08.
^ Hyperpigmentation on Face (Acne Scars} Hyperpigmentation, Dark Spots, Acne Scars, Meladerm".

External links

Dark Spot Remover

UpToDate Contents

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1. 色素沈着過剰を有する患者へのアプローチ approach to the patient with hyperpigmentation disorders
2. 炎症後色素沈着過剰症 postinflammatory hyperpigmentation
3. 斑状の皮膚病変を有する患者へのアプローチ approach to the patient with macular skin lesions
4. 皮膚色素過剰症に対するレーザーおよび光線療法 laser and light therapy for cutaneous hyperpigmentation
5. 肝斑 melasma

English Journal

Hordenine, a single compound produced during barley germination, inhibits melanogenesis in human melanocytes.

Kim SC, Lee JH, Kim MH, Lee JA, Kim YB, Jung E, Kim YS, Lee J, Park D.SourceBiospectrum Life Science Institute, Eines Platz 11th FL, #442-13 Sangdaewon Dong, Seongnam City, 462-807 Gyunggi Do, Republic of Korea.
Food chemistry.Food Chem.2013 Nov 1;141(1):174-81. doi: 10.1016/j.foodchem.2013.03.017. Epub 2013 Mar 14.
Melanin plays an important role protecting skin against ultraviolet light injury. However, increased production and accumulation of melanin results in a large number of skin disorders. Here, we identified hordenine as an active compound from germinated barley (Hordeum vulgare L.) and investigated th
PMID 23768344

Characterization of a small molecule inhibitor of melanogenesis that inhibits tyrosinase activity and scavenges nitric oxide (NO).

Chung KW, Jeong HO, Jang EJ, Choi YJ, Kim DH, Kim SR, Lee KJ, Lee HJ, Chun P, Byun Y, Moon HR, Chung HY.SourceMolecular Inflammation Research Center for Aging Intervention (MRCA), Department of Pharmacy, Pusan National University, Busan 609-735, Republic of Korea.
Biochimica et biophysica acta.Biochim Biophys Acta.2013 Oct;1830(10):4752-61. doi: 10.1016/j.bbagen.2013.06.002. Epub 2013 Jun 12.
BACKGROUND: Excessive melanin production and accumulation are characteristics of a large number of skin diseases, including melasma, and post-inflammatory hyperpigmentation. During our on-going search for new agents with an inhibitory effect on tyrosinase, we synthesized a new type of tyrosinase inh
PMID 23769841

Topical ozonated oil versus hyaluronic gel for the treatment of partial- to full-thickness second-degree burns: A prospective, comparative, single-blind, non-randomised, controlled clinical trial.

Campanati A, De Blasio S, Giuliano A, Ganzetti G, Giuliodori K, Pecora T, Consales V, Minnetti I, Offidani A.SourceDermatology Clinic, Department of Clinical Medicine and Biotechnology, Polytechnic University of Marche, Ancona, Italy. Electronic address: a.campanati@univpm.it.
Burns : journal of the International Society for Burn Injuries.Burns.2013 Sep;39(6):1178-83. doi: 10.1016/j.burns.2013.03.002. Epub 2013 Apr 8.
INTRODUCTION AND AIM: Several studies have demonstrated that ozonated oil is effective on cutaneous wound healing. This in vivo study has been conducted to evaluate the clinical effect of the topical application of ozonated oil for 12 weeks on second-degree skin burns.METHOD: A total of 30 patients
PMID 23579036

Japanese Journal

症例塩酸ミノサイクリンによる色素沈着症

佐藤仁美,湊原一哉
皮膚科の臨床 53(6), 845-849, 2011-06
NAID 40018873460

In Vitro and Vivo Melanogenesis Inhibition by Biochanin A from Trifolium pratense

LIN Victor C.,DING Hsiou-Yu,TSAI Pin-Chin,WU Jiumn-Yih,LU Yen-Hsing,CHANG Te-Sheng
Bioscience, biotechnology, and biochemistry 75(5), 914-918, 2011-05-23
… Biochanin A was confirmed as a good candidate for use as a skin-whitening agent in the treatment of skin hyperpigmentation disorders. …
NAID 10028272626