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Hyperpigmentation
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.James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. . People with darker 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. The process of melanin synthesis (melanogenesis) starts with the oxidation of -tyrosine to by the enzyme tyrosine hydroxylase, then to -dopaquinone and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acne Vulgaris
Acne, also known as ''acne vulgaris'', is a long-term skin condition that occurs when dead skin cells and oil from the skin clog hair follicles. Typical features of the condition include blackheads or whiteheads, pimples, oily skin, and possible scarring. It primarily affects skin with a relatively high number of oil glands, including the face, upper part of the chest, and back. The resulting appearance can lead to anxiety, reduced self-esteem, and, in extreme cases, depression or thoughts of suicide. Susceptibility to acne is primarily genetic in 80% of cases. The roles of diet and cigarette smoking in the condition are unclear, and neither cleanliness nor exposure to sunlight appear to play a part. In both sexes, hormones called androgens appear to be part of the underlying mechanism, by causing increased production of sebum. Another common factor is the excessive growth of the bacterium ''Cutibacterium acnes'', which is present on the skin. Treatments for acne are ava ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acne Vulgaris
Acne, also known as ''acne vulgaris'', is a long-term skin condition that occurs when dead skin cells and oil from the skin clog hair follicles. Typical features of the condition include blackheads or whiteheads, pimples, oily skin, and possible scarring. It primarily affects skin with a relatively high number of oil glands, including the face, upper part of the chest, and back. The resulting appearance can lead to anxiety, reduced self-esteem, and, in extreme cases, depression or thoughts of suicide. Susceptibility to acne is primarily genetic in 80% of cases. The roles of diet and cigarette smoking in the condition are unclear, and neither cleanliness nor exposure to sunlight appear to play a part. In both sexes, hormones called androgens appear to be part of the underlying mechanism, by causing increased production of sebum. Another common factor is the excessive growth of the bacterium ''Cutibacterium acnes'', which is present on the skin. Treatments for acne are ava ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthosis Nigricans
Acanthosis nigricans is a medical sign characterised by brown-to-black, poorly defined, velvety hyperpigmentation of the skin. It is usually found in body folds, such as the posterior and lateral folds of the neck, the armpits, groin, navel, forehead and other areas. It is associated with endocrine dysfunction, especially insulin resistance and hyperinsulinaemia, as seen in diabetes mellitus. This activates the insulin-like growth factor receptors, which leads to proliferation of keratinocytes, fibroblasts and other cells in the skin. Activation of other growth factor receptors such as fibroblast growth factor receptors or epidermal growth factor receptor can also be responsible. Signs and symptoms Acanthosis nigricans may present with thickened, velvety, relatively darker areas of skin on the neck, armpit and in skin folds. Causes It typically occurs in individuals younger than age 40, is associated with insulin resistance, Type 2 diabetes, obesity or endocrinopathies, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melasma
Melasma (also known as chloasma faciei,James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. . or the mask of pregnancy when present in pregnant women) 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. Signs and symptoms The symptoms of melasma are dark, irregular, well-demarcated, hyperpigmented macules to patches. These patches often develop gradually over time. Melasma does not cause any other symptoms beyond the cosmetic discoloration. Patches can vary in size from 0.5 cm to larger than 10 cm depending on the person. Its location can be categorized as centrofacial, malar, or mandibular. The most common is ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloasma
Melasma (also known as chloasma faciei,James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. . or the mask of pregnancy when present in pregnant women) 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. Signs and symptoms The symptoms of melasma are dark, irregular, well-demarcated, hyperpigmented macules to patches. These patches often develop gradually over time. Melasma does not cause any other symptoms beyond the cosmetic discoloration. Patches can vary in size from 0.5 cm to larger than 10 cm depending on the person. Its location can be categorized as centrofacial, malar, or mandibular. The most common is ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linea Nigra
Linea nigra (Latin for "black line"), often referred to as a pregnancy line, is a linear hyperpigmentation that commonly appears on the abdomen. The brownish streak is usually about a centimeter (0.4 in) in width. The line runs vertically along the midline of the abdomen from the pubis to the umbilicus, but can also run from the pubis to the top of the abdomen. For pregnant women, linea nigra is attributed to increased melanocyte-stimulating hormone made by the placenta, which also causes melasma and darkened nipples. Fair-skinned women show this phenomenon less often than women with darker pigmentation. Linea nigra typically disappears within a few months after delivery. Although linea nigra is rarely discussed outside pregnancy, males and females of all ages may have it. Except in pregnancy, both sexes have highest and equal prevalence of linea nigra from age 11 to 15. This increase in prevalence could be the result of hormonal changes during puberty. After age 15, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanocyte-stimulating Hormone
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. Synthetic analogues of α-MSH, such as afamelanotide (melanotan I; Scenesse), melanotan II, and bremelanotide (PT-141), have been developed and researched. Biosynthesis The various forms of MSH are generated from different cleavages of the proopiomelanocortin protein, which also yields other important neuropeptides like adrenocorticotropic hormone. Melanocytes in skin make and secrete MSH in response to ultraviolet light, where it increases synthesis of melanin. Some neurons in arcuate nucleus of the hypothalamus make and secrete α-MSH in response to leptin; α-MSH is also m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanocytes
Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea), the inner ear, vaginal epithelium, meninges, bones, and heart. 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. Function Through a process called melanogenesis, melanocytes produce melanin, which is a pigment found in the skin, eyes, hair, nasal cavity, and inner ear. This melanogenesis leads to a long-lasting pigmentation, which is in contrast to the pigmentation that originates from oxidation of already-existing melanin. There are both ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adrenal Insufficiency
Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones. The adrenal gland normally secretes glucocorticoids (primarily cortisol), mineralocorticoids (primarily aldosterone), and androgens. These hormones are important in regulating blood pressure, electrolytes, and metabolism as a whole. Deficiency of these hormones leads to symptoms ranging from abdominal pain, vomiting, muscle weakness and fatigue, low blood pressure, depression, mood and personality changes (in mild cases) to organ failure and shock (in severe cases). An adrenal crisis may occur if the body is subjected to stress, such as an accident, injury, surgery, or severe infection; this is a life-threatening medical condition resulting from severe deficiency of cortisol in the body. Death may quickly follow. Adrenal insufficiency can be caused by dysfunction of the adrenal gland itself, whether by destruction (e.g. Addison's disease), failure of development ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Addison's Disease
Addison's disease, also known as primary adrenal insufficiency, is a rare long-term endocrine disorder characterized by inadequate production of the steroid hormones cortisol and aldosterone by the two outer layers of the cells of the adrenal glands (adrenal cortex), causing adrenal insufficiency. Symptoms generally come on slowly and insidiously and may include abdominal pain and gastrointestinal abnormalities, weakness, and weight loss. Darkening of the skin in certain areas may also occur. Under certain circumstances, an adrenal crisis may occur with low blood pressure, vomiting, lower back pain, and loss of consciousness. Mood changes may also occur. Rapid onset of symptoms indicates acute adrenal failure which is a serious and emergent condition. An adrenal crisis can be triggered by stress, such as from an injury, surgery, or infection. Addison's disease arises from problems with the adrenal gland such that not enough of the steroid hormone cortisol and possibly aldo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adrenocorticotropic Hormone
Adrenocorticotropic hormone (ACTH; also adrenocorticotropin, corticotropin) is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland. It is also used as a medication and diagnostic agent. ACTH is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress (along with its precursor corticotropin-releasing hormone from the hypothalamus). Its principal effects are increased production and release of cortisol by the cortex of the adrenal gland. ACTH is also related to the circadian rhythm in many organisms. Deficiency of ACTH is an indicator of secondary adrenal insufficiency (suppressed production of ACTH due to an impairment of the pituitary gland or hypothalamus, cf. hypopituitarism) or tertiary adrenal insufficiency (disease of the hypothalamus, with a decrease in the release of corticotropin releasing hormone (CRH)). Conversely, chronically elevated ACTH levels occur in primary ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through transepidermal water loss. The epidermis is composed of multiple layers of flattened cells that overlie a base layer (stratum basale) composed of columnar cells arranged perpendicularly. The layers of cells develop from stem cells in the basal layer. The human epidermis is a familiar example of epithelium, particularly a stratified squamous epithelium. The word epidermis is derived through Latin , itself and . Something related to or part of the epidermis is termed epidermal. Structure Cellular components The epidermis primarily consists of keratinocytes ( proliferating basal and differentiated suprabasal), which comprise 90% of its cells, but also contains melanocytes, Langerhans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
