NationMaster - Encyclopedia: Itch

Itch (Latin: pruritus) is defined as an unpleasant sensation that evokes the desire or reflex to scratch. Itch has many similarities to pain and both are unpleasant sensory experiences but their behavioral response patterns are different. Pain creates a reflex withdrawal while itch leads to a scratch reflex.^[1] Unmyelinated nerve fibers for itch and pain both originate in the skin, however information for them is conveyed centrally in two distinct systems that both use the same peripheral nerve bundle and spinothalamic tract.^[2] Look up itch in Wiktionary, the free dictionary. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // L00-L99 - Diseases of the skin and subcutaneous tissue (L00-L08) Infections of the skin and subcutaneous tissue (L00) Staphylococcal scalded skin syndrome (L01) Impetigo (L02) Cutaneous abscess, furuncle and carbuncle (L03) Cellulitis (L04) Acute lymphadenitis (L05) Pilonidal cyst (L08) Other local infections of skin and subcutaneous tissue (L081) Erythrasma... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... MedlinePlus (medlineplus. ... For other uses, see Latin (disambiguation). ... It has been suggested that this article or section be merged with Sensation and perception psychology. ... For other uses, see Reflexive (disambiguation). ... Look up scratch in Wiktionary, the free dictionary. ... Look up Pain in Wiktionary, the free dictionary. ... For other uses, see Skin (disambiguation). ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system--to serve the limbs and organs, for example. ... The spinothalamic tract is a sensory pathway originating in the spinal cord that transmits information about pain, temperature, itch and crude touch to the thalamus. ...

Historically, the sensations of itch and pain have not been considered to be independent of each other until recently where it was found that itch has several features in common with pain but exhibits notable differences.^[3] The physiological mechanisms of itch are currently poorly understood and this is mainly due to the lack of animal models of itch. Pruritic stimuli mostly create the same reactions as noxious stimuli in experimental animals, but humans are capable of discerning the distinct features of itch and pain. Therefore human studies have provided most of the information regarding the processing of pruritic stimuli.^[4]

Mechanism

Itch can originate in the peripheral nervous system (dermal or neuropathic) or in the central nervous system (neuropathic, neurogenic, or psychogenic).^[5]

Dermal/Pruritoceptive

Itch originating in the skin is considered pruritoceptive and can be induced by a variety of stimuli, including mechanical, chemical, thermal, and electrical stimulation. The primary afferent neurons responsible for histamine induced itch are unmyelinated C-fibers. In human C-fiber nociceptors, two major classes exist: mechano-responsive nociceptors and mechano-insensitive nociceptors. Mechano-responsive nociceptors have been shown in studies to respond to mostly pain and mechano-insensitive receptors respond mostly to itch induced by histamine. However it does not explain mechanically induced itch or when itch is produced without a flare reaction which involves no histamine. Therefore it is possible that pruritoceptive nerve fibers have different classes of fibers, which is currently unclear in current research.^[1] A nociceptor is a sensory receptor that responds only after a high level of stimuli or a level enough to hurt the individual. ...

Studies have been done to show that itch receptors are only found on the top two skin layers, the epidermis and the epidermal/dermal transition layers. Shelley and Arthur had verified the depth by injecting individual itch powder spicules (Mucuna pruriens) and found that maximal sensitivity was found at the basal cell layer or the innermost layer of the epidermis. Surgical removal of those skin layers removed the ability for a patient to perceive itch. Itch is never felt in muscle, joints, or inner organs, which show that deep tissue does not contain itch signaling apparatuses.^[3] This article is about the skeletal structure. ... Binomial name Mucuna pruriens (L.) DC. Mucuna pruriens (syn. ...

Sensitivity to pruritic stimuli is not even across the skin and has a random spot distribution with similar density to that of pain. The same substances that elicit itch upon intracutaneous injection (injection within the skin) elicit only pain when injected subcutaneously (beneath the skin). Itch is readily abolished in skin areas treated with nociceptor excitotoxin capsaicin but remains unchanged in skin areas which were rendered touch-insensitive by pretreatment with saponins, an anti-inflammatory agent. Although experimentally induced itch can still be perceived under a complete A-fiber conduction block, it is significantly diminished. Overall, itch sensation is mediated by A-delta and C nociceptors located in the uppermost layer of the skin.^[6] Saponins are the glycosides of 27 carbon atom steroids, or 30 carbon atom triterpenes. ...

Neuropathic

Neuropathic itch can originate at any point along the afferent pathway as a result of damage of the nervous system. They could include diseases or disorders in the central nervous system or peripheral nervous system.^[3] Examples of neuropathic itch in origin are nostalgia paresthetica, brachioradial pruritus, brain tumors, multiple sclerosis, peripheral neuropathy, and nerve irritation.^[7]

Neurogenic

Neurogenic itch, which is itch induced centrally but with no neural damage, is often associated with increased accumulation of endogenous opioids and possibly synthetic opioids.^[3] An opioid is any agent that binds to opioid receptors found principally in the central nervous system and gastrointestinal tract. ...

Psychogenic

Itch is also associated with some psychiatric disorders such as delusions of parasitosis or related obsessive-compulsive disorders, for example neurotic scratching.^[3]

Interactions between Itch and Pain

Pain Inhibits Itch

The sensation of itch can be reduced by many painful sensations. Many studies done in the last decade have shown that itch can be inhibited by many other forms of painful stimuli, such as noxious heat, physical rubbing/scratching, noxious chemicals, and electric shock. Any stimulus that causes pain will inhibit itching.

The inhibition of itch by painful stimuli, including heat, physical stimulus, and chemical stimulus, has been shown experimentally. In an article written by Louise Ward and others, they studied the effects of noxious and non-noxious counterstimuli, such as heat, physical vibration, or chemical stimulation on skin, in healthy adults after they had experimentally induced itch (transdermal iontophoresis of histamine) and pain (with topical mustard oil) in their skin. They found that when they induced non-noxious counterstimuli, the reduction of pain and itch was reduced only for up to 20 seconds. However when they induced noxious counterstimuli, there was a significant inhibition of itch for an extended period of time but no inhibition of pain. In addition, it was found that brief noxious stimuli created an anti-itch state for more than 30 minutes. These findings show that itch is not a subliminal form of pain and that noxious counterstimulus is likely to act through a central instead of a peripheral mechanism.^[4]

Painful electrical stimulation reduced histamine-induced itch for several hours at a distance up to 10 cm from the stimulated site, which suggests a central mode of action. A new method had been recently found, by Hans-Jorgen Nilsson and others, that is able to relieve itch without damaging the skin called cutaneous field stimulation (CFS). CFS consists of a flexible rubber plate with 16 needle-like electrodes placed regularly at 2-centimeter intervals in a 4 by 4 matrix used to electrically stimulate nerve fibers in the surface of the skin. The electrodes were stimulated continuously at 4 Hertz per electrode, pulse duration of 1 millisecond, intensity 0.4-0.8 milliamperes, and for 25 minutes. CFS resulted in a pricking and burning sensation that usually faded away very quickly. The burning sensation was still present during a selective block of impulse conduction of A-fibers in myelinated fibers indicating that nociceptive C-fibers are activated by CFS. In addition, a flare reaction had been noted to develop around the CFS electrodes which indicate activation of axon reflexes in nociceptive C-fibers. Itch, which was induced by transdermal iontophoresis of histamine, was inhibited within the skin area treated with CFS, and it was reduced 10 cm distally to a significant amount. CFS proves to offer a new method of combating itch by using painful electrical stimulation as it creates a long lasting inhibitory effect, does not create any significant skin injuries, and is simple to manage. It is able to activate powerful itch inhibitory mechanisms possibly routed through central mechanisms, which could normally be activated by scratching of the skin.^[8]

A study done by Gil Yosipovitch, Katharine Fast, and Jeffrey Bernhard showed that noxious heat and scratching was able to inhibit or decrease itch induced by transdermal iontophoresis of histamine and most interestingly, decrease skin blood flow. Twenty-one healthy volunteers participated in their study. Baseline measurements of skin blood flow were obtained on the flexor part of the forearm and then compared with skin blood flow after various stimuli. Then transdermal iontophoresis of histamine was performed and tested with various stimuli. It is well known that skin blood flow is significantly increased during mechanical scratching, warming, and noxious heat. However it is quite interesting that this study is the first to examine the changes of blood flow by stimuli during iontophoresis of histamine and how itch is perceived in those conditions. Its examination provided an unexpected result that noxious heat and scratching has an inhibitory effect.^[9]

A negative correlation was found between pain sensitivity and itch sensitivity. In a study done by Amanda Green and others, they aimed to determine itch-related genetic factors, and establish a more useful animal model for itch. They looked at 11 different inbred mouse strains and compared their scratching behavior in response to two itch inducing agents, histamine and chloroquine. Every strain revealed an inverted-U shape dose response relationship from chloroquine, indicating that moderate dosages produced more scratching than at higher dosages. An explanation is that higher dosage produces more pain and the presence of pain inhibits pain thereby lowering the amount of overall scratching. Another notable result was that histamine induced scratching occurred in female mice on average 23% more than males. Finally, it was found that mice having strains sensitive to pain were resistant to itch and vice versa.^[10]

Peripheral Sensitization

Inflammatory mediators such as bradykinin, serotonin (5-HT) and prostaglandins, released during a painful or pruritic inflammatory condition not only activates pruriceptors but also causes acute sensitization of the nociceptors. In addition, expression of neuro growth factors (NGF) can cause structural changes in of nociceptors such as sprouting. NGF is high in injured or inflamed tissue. Increased NGF is also found in atopic dermatitis, a hereditary and non-contagious skin disease with chronic inflammation.^[11] NGF is known to up-regulate neuropeptides, especially substance P. Substance P has been found to have an important role in inducing pain however there is no confirmation that substance P directly causes acute sensitization. Instead substance P may contribute to itch by increasing neuronal sensitization and may the affect release of mast cells, which contain many granules rich in histamine, during long-term interaction.^[1]

Central Sensitization

Noxious input to the spinal cord is known to produce central sensitization, which consists of allodynia, exaggeration of pain, and punctuate hyperalgesia, extreme sensitivity to pain. Two types of mechanical hyperalgesia can occur: 1) touch that is normally painless in the uninjured surroundings of a cut or tear can trigger painful sensations (touch-evoked hyperalgesia), and 2) a slightly painful pin prick stimulation is perceived as more painful around a focused area of inflammation (punctuate hyperalgesia). Touch-evoked hyperalgesia requires continuous firing of primary afferent nociceptors, and punctuate hyperalgesia does not require continuous firing which means it can persist for hours after a trauma and can be stronger than normally experienced. In addition, it was found that patients with neuropathic pain, histamine ionophoresis resulted in a sensation of burning pain rather than itch, which would be induced in normal healthy patients. This shows that there is spinal hypersensitivity to C-fiber input in chronic pain.^[1]

Causes

The feeling of itchiness can be caused by a movement of hair or the release of a chemical (histamine) from cells under the skin. Itchiness is regarded as protective, as it helps creatures remove parasites that land on their skin. Image File history File linksMetadata Scabies-burrow. ... Image File history File linksMetadata Scabies-burrow. ... This article or section does not cite any references or sources. ... A parasite is an organism that lives in or on the living tissue of a host organism at the expense of it. ...

Xerosis is the medical term for dry skin. ... Dermatology (from Greek Î´ÎµÏÎ¼Î±, skin) is a branch of medicine dealing with the skin and its appendages (hair, sweat glands, etc). ... For the beetle, see Exema. ... Athletes foot or Tinea pedis[1] is a parasitic fungal infection of the epidermis of the foot. ... Hidradenitis suppurativa or HS is a skin disease that affects areas bearing apocrine sweat glands and hair follicles; such as the underarms, groin and buttocks. ... This article is about the insect; for the WWII aircraft see De Havilland Mosquito. ... The term chigger (or jigger) can refer to either of two distinct parasitic arthropods with similar behaviors. ... For information on urushiol poisoning, see Urushiol-induced contact dermatitis. ... Binomial name Toxicodendron radicans (L.) Kuntze Poison-ivy (Toxicodendron radicans or Rhus toxicodendron), in the family Anacardiaceae, is a woody vine that is well-known for its ability to produce urushiol, a skin irritant which for most people will cause an agonizing, itching rash. ... Binomial name Toxicodendron diversilobum Western poison oak (Toxicodendron diversilobum or, previously, Rhus diversiloba) is found only on the Pacific Coast of the United States and of Canada. ... Hodgkins disease is a type of lymphoma described by Thomas Hodgkin in 1832, and characterized by the presence of Reed-Sternberg cells. ... Look up jaundice in Wiktionary, the free dictionary. ... Bilirubin is a yellow breakdown product of normal heme catabolism. ... Polycythemia is a condition in which there is a net increase in the total number of red blood cells in the body. ... Suborders Anoplura (sucking lice) Rhyncophthirina Ischnocera (avian lice) Amblycera (chewing lice) Lice (singular: louse) (order Phthiraptera) are an order of over 3000 species of wingless parasitic insects. ... For other uses, see Worm (disambiguation). ... This article is about the use of a razor. ... For the disease characterized by excretion of large amounts of very dilute urine, see diabetes insipidus. ... For the album by Ivor Cutler, see Dandruff (album). ... For a more specific and detailed discussion of anemia caused by iron deficiency, see the Wikipedia article iron deficiency anemia. ... This article discusses the medical condition. ... Psychiatry is a branch of medicine that studies and treats mental and emotional disorders (see mental illness). ... Allergy is an abnormal reaction to a substance foreign to the body that is acquired, predictable and rapid. ... Photodermatitis is a reaction of the skin to UV rays of the sun. ... This article is about the drug. ... An opioid is any agent that binds to opioid receptors found principally in the central nervous system and gastrointestinal tract. ... In medicine, cholestasis is a condition where bile cannot flow from the liver to the duodenum. ... Pruritic Urticarial Papules and Plaques of Pregnancy (PUPPP), known in United Kingdom as Polymorphic eruption of pregnancy (PEP),[1] is a chronic hives-like rash that strikes some women during pregnancy. ... Gestational Pemphigoid or Pemphigoid Gestationis (PG) is a rare autoimmune blistering skin disease that occurs during pregnancy, typically in the second or third trimester, and/or immediately following pregnancy. ...

Treatment

A variety of over-the-counter and prescription anti-itch drugs are available. Some plant products have been found to be effective anti-pruritics, others not. Non-chemical remedies include cooling, warming, soft stimulation. Antipruritics, also known as anti-itch drugs, are medications that inhibit the itching (Latin: pruritus) that is often associated with sunburns, allergic reactions, eczema, psoriasis, chickenpox, fungal infections, insect bites and stings like those from mosquitoes, fleas, and mites, and contact dermatitis and urticaria caused by plants such as poison...

Sometimes scratching relieves isolated itches, hence the existence of devices such as the back scratcher. Often, however, scratching can intensify itching and even cause further damage to the skin, dubbed the "itch-scratch-itch cycle". A common wooden backscratcher in action relieving an itch A backscratcher (occasionally known as a scratch-back or magonote) is a tool used, as the name would suggest, for relieving itches for areas that cannot be reached just by ones own hands, typically the back. ...

The mainstay of therapy for dry skin is maintaining adequate skin moisture and topical emollients. Emollients soften skin (and moisturisers add moisture). ...

Sensations Associated with Scratching

Pain and itch have very different behavioral response patterns. Pain evokes a withdrawal reflex which leads to retraction and therefore a reaction trying to protect an endangered part of the body. Itch creates a scratching reflex which draws one to the affected skin site. For example, responding to a local itch sensation is an effective way to remove insects on the skin. Scratching has traditionally been regarded as a way to relieve one self by reducing the annoying itch sensation. However there are hedonic aspects of scratching as one would find noxious scratching highly pleasurable.^[1] This can be problematic with chronic itch patients, such as ones with atopic dermatitis, who may scratch affected spots until it no longer produces a pleasant or painful sensation instead of when the itch sensation disappears.^[12] It has been hypothesized that motivational aspects of scratching include the frontal brain areas of reward and decision making. These aspects might therefore contribute to the compulsive nature of itch and scratching.^[1]

Contagious Itch

Events of “contagious itch” are very common occurrences. Even a discussion on the topic of itch can give one the desire to scratch. Itch is likely more than a localized phenomenon in the place we scratch. Results from a recent study showed that itching and scratching were induced purely by visual stimuli in a public lecture on itching. There is currently little detailed data on central activation for contagious itching but it is hypothesized that a human mirror neuron system exists in which we imitate certain motor actions when we view others performing the same action. A similar phenomenon in which mirror neurons are used to explain the cause is contagious yawning.^[1]

See also

Referred itch (also known as Mitempfindung) is a phenomenon experienced by about one person in four[1], where scratching an itch on one part of the body produces an itching sensation on a different, apparently unrelated part of the body. ... A domestic cat grooming itself by licking its fur clean Personal grooming, sometimes called preening, or simply grooming, is the art of cleaning, grooming, and maintaining parts of the body. ...

References

External links

GPnotebook is a British medical database for general practitioners (GPs. ... The Family Practice Notebook is a medical database focused on family practice. ... For other uses, see Skin (disambiguation). ... The subcutis is the layer of tissue directly underlying the cutis. ... In zootomy, the integumentary system is the external covering of the body, comprising the skin, hair, scales, nails, sweat glands and their products (sweat and mucus). ... An infection is the detrimental colonization of a host organism by a foreign species. ... Species S. aureus S. caprae S. epidermidis S. haemolyticus S. hominis S. lugdunensis S. pettenkoferi S. saprophyticus S. warneri S. xylosus Staphylococcus (in Greek staphyle means bunch of grapes and coccos means granule) is a genus of Gram-positive bacteria. ... Boil or furuncle is a skin disease caused by the inflammation of hair follicles, thus resulting in the localized accumulation of pus and dead tissues. ... For other uses, see Carbuncle (disambiguation). ... This article is about the nail disease. ... Species See text. ... Erythrasma is a skin disease that can result in pink patches, which can turn into brown scales. ... For the packaging type, see Blister pack. ... Pemphigus is an autoimmune disorder that causes blistering and raw sores on skin and mucous membranes. ... Bullous pemphigoid, also referred to as BP, is a chronic autoimmune skin disease, involving the formation of blisters below the surface of the skin and antibodies against collagen XVII. It can also (albeit only rarely) involve the mucous membranes, and has been shown to afflict dogs, cats, pigs, and horses... Dermatitis herpetiformis (DH) or Duhrings Disease, is a skin disorder often associated with celiac disease. ... Dermatitis is a blanket term literally meaning inflammation of the skin. It is usually used to refer to eczema, which is also known as Dermatitis eczema. ... For the beetle, see Exema. ... For the album by Ivor Cutler, see Dandruff (album). ... An infant with Cradle Cap Close up image of Cradle Cap Cradle Cap (Infantile seborrhoeic dermatitis, or crusta lactea, milk crust, honeycomb disease; croÃ»te de lait, eczÃ©ma infantile, dermatite atopique infantile (French); ne shqip njihet si - rrjebull ose rrjebulla (Albanian); crosta lattea (Italian); and ÏƒÎ¼Î·Î³Î¼Î±Ï„ÏŒÏÏÎ¿Î¹Î± Ï„Î¿Ï… Ï„ÏÎ¹Ï‡Ï‰Ï„Î¿Ï Ï„Î·Ï‚ ÎºÎµÏ†Î±Î»Î®Ï‚ Ï„Ï‰Î½ Î½ÎµÎ¿Î³Î½ÏŽÎ½ (Greek)) is a patchy... Diaper rash (U.S.) or nappy rash (UK), is a generic term applied to skin rashes in the diaper area that are caused by a various skin disorders and/or irritants. ... Toxicodendron pubescens (Atlantic Poison-oak), one of a large number of species containing urushiol irritants. ... Contact dermatitis is a term for a skin reaction resulting from exposure to allergens or irritants. ... Erythroderma refers to a skin disorder characterized by the widespread reddening of the skin. ... Lichen simplex chronicus is a skin disorder characterized by chronic itching and scratching. ... Prurigo nodularis (PN) is a skin disease characterised by pruritic (itchy) nodules which usually appear on the arms or legs. ... Pruritus ani is a medical term which refers to persistent itching of the anus (and in Latin means literally the same thing). ... Nummular dermatitis is one of the many forms of dermatitis. ... Late stage of dyshidrosis on the hands Also known as Dyshidrotic Eczema Dyshidrotic Dermatitis Pompholyx Dyshidrosis is a skin condition that is characterized by small blisters on the hands or feet. ... Pityriasis alba is a common skin condition mostly occurring in children and usually seen as dry, fine scaled, pale patches on their faces. ... A papulosquamous disorder is a condition which presents with both papules and scales,[1] or both scaly papules and plaques. ... Psoriatic arthritis (or Arthropathic psoriasis) is a type of inflammatory arthritis that affects around 20% of people suffering from the chronic skin condition Psoriasis. ... Parapsoriasis refers to one of a group of skin disorders that are characterized primarily by their resemblance to psoriasis (red, scaly lesions), rather than by their underlying etiology. ... Pityriasis Lichenoides et Varioliformis Acuta, or Mucha Habermanns Disease, short form PLEVA, is a disease of the immune system. ... Pityriasis lichenoides chronica is the chronic version of the Pityriasis lichenoides et varioliformis acuta, also called Mucha Habermanns Disease. ... Pityriasis rosea is a skin disease marked by patches of pink, oval rash. ... Lichen planus is an inflammatory disease that affects the skin and the oral mucosa. ... Pityriasis Rubra Pilaris (PRP) is a chronic rare skin disorder characterized by reddish orange color of the skin, and scaling, flaky skin. ... Lichen nitidus is a chronic inflammatory disease of unknown etiology[1], characterized by 1-2mm, discrete and uniform, shiny, flat-topped, pale flesh-colored or reddish-brown papules[2][3] that may be hypopigmented in blacks, and, occasionally, minimal scaling is present or can be induced by rubbing the surface... Erythema is redness of the skin caused by capillary congestion. ... Seen in about 5 percent of the population, Dermatographism is caused by Mast cells in the surface of the skin releasing histamines upon light scratching of the skins surface. ... Cholinergic urticaria is subcategory of physical urticaria (aka hives) that is a skin rash brought on by a hypersensitive reaction to body heat. ... Erythema is redness of the skin caused by capillary congestion. ... Stevens-Johnson syndrome (SJS) is a severe and potentially life-threatening (15% of cases) disease, it is a hypersensitivity complex affecting the skin and the mucous membranes, a severe expression of erythema multiforme (EM) (and so SJS is also called erythema multiforme major). ... Stevens-Johnson syndrome (SJS) is a severe and life-threatening condition. ... Toxic epidermal necrolysis is a life-threatening and usually drug-induced dermatological condition that occurs more often in women than in men. ... Erythema nodosum is a form of inflammation of the subcutaneous fatty tissue. ... Erythema annulare centrifugum is a descriptive term for a skin lesion consisting of redness (=erythema) in a ring form (=annulare) that spreads from the center (= centrifugum). ... Erythema marginatum is described as the presence of pink rings on the trunk and inner surfaces of the arms and legs which come and go for as long as several months. ... For other uses, see Radiation (disambiguation). ... Actinic keratosis (also called solar keratosis, or AK) is a premalignant condition of thick, scaly, or crusty patches of skin. ... Polymorphic Light Eruption (PLE) is a skin complaint caused by sunlight. ... Radiodermatitis is a skin disease associated with prolonged exposure to radiation. ... Erythema ab igne (EAI, or dermatitis ab igne) refers to skin that is reddened due to repeated exposure to heat radiation. ... Skin appendages are appendages that are associated with the skin and serve a particular function. ... Nail diseases are in a separate category from diseases of the skin. ... Onychocryptosis, commonly known as ingrown nails (unguis incarnatus) or ingrowing nails, is a common form of nail disease. ... Onychogryposis, also called rams-horn nail, is a thickening and increase in curvature of the nail. ... Beaus lines: Deep grooved lines that run from side to side on the fingernail. ... Yellow Nail Syndrome is the term that describes the triad of pleural effusions, lymphoedema and yellow dystrophic nails. ... Alopecia is a set of disorders ranging from male and female pattern alopecia (alopecia androgenetica), to alopecia areata, which involves the loss of some of the hair from the head, alopecia totalis, which involves the loss of all head hair, to the most extreme form, alopecia universalis, which involves the... Alopecia totalis is the loss of all head hair. ... Alopecia universalis is a medical disorder in which the afflicted are unable to grow hair on the entire body. ... Ophiasis is a form of alopecia areata characterized by the the loss of hair in the shape of a wave at the circumference of the head. ... Telogen Effluvium is characterized by sudden, diffuse hair loss caused by an interruption in the normal hair growth cycle. ... A form of Alopecia (gradual hair loss) caused primarily by pulling force being applied to the hair. ... Lichen planus is an inflammatory disease that usually affects the skin, the mouth, or sometimes both. ... Trichorrhexis nodosa is a defect in the hair shaft characterized by thickening or weak points (nodes) that cause the hair to break off easily. ... Hypertrichosis is a medical term, also known as Wolfitis, referring to a condition of excessive body hair. ... Hirsutism (from Latin hirsutus = shaggy, hairy) is defined as excessive and increased hair growth in women in locations where the occurrence of terminal hair normally is minimal or absent. ... This article is about a skin disease commonly found during adolescence. ... Rosacea (IPA: ) is a common but often misunderstood condition that is estimated to affect over 45 million people worldwide. ... Perioral dermatitis Perioral dermatitis, a condition related to acne vulgaris, consists of red superficial pustules around the mouth and chin and the sides of the nose. ... Rhinophyma is a descriptive term for a large, bulbous, ruddy appearance of the nose caused by granulomatous infiltration. ... An epidermoid cyst is a benign cyst, developed out of ectodermal tissue. ... Close-up of an infected sebaceous cyst that has abscessed, located behind the ear lobe. ... Steatocystoma multiplex is a congenital conditions resulting in multiple cysts on the body. ... Pseudofolliculitis barbae (pronounced //) is a medical term for persistent inflammation caused by shaving. ... Hidradenitis suppurativa or HS is a skin disease that affects areas bearing apocrine sweat glands and hair follicles; such as the underarms, groin and buttocks. ... Folliculitis is inflammation of one or more hair follicles. ... A diagrammatic sectional view of the skin (magnified). ... Not to be confused with malaria. ... Anhidrosis means lack of sweating. ... Sweating (also called perspiration or sometimes transpiration) is the loss of a watery fluid, consisting mainly of sodium chloride and urea in solution, that is secreted by the sweat glands in the skin of mammals. ... Bromhidrosis or body odor (also called bromidrosis, osmidrosis and ozochrotia) is the smell of bacteria growing on the body. ... Chromhidrosis is a rare condition characterized by the secretion of colored sweat. ... Fox-Fordyce disease is a chronic blockage of the sweat gland ducts with a secondary, nonbacterial inflammatory response to the secretions and cellular debris in the cysts. ... Not to be confused with alphos, a form of leprosy once called vitiligo. ... Melasma (also known as chloasma or the mask of pregnancy when present in pregnant women) is a tan or dark facial skin discoloration. ... Freckles are small colored spots of melanin on the exposed skin or membrane of people with complexions fair enough for them to be visible. ... CafÃ© au lait spots or cafe-au-lait spots (CAL) are pigmented birthmarks. ... Lentigo is a type of brown skin lesion. ... Liver spots are blemishes on the skin associated with ageing and exposure to ultra-violet radiation from the sun. ... Seborrheic keratosis (Seborrhoeic keratosisis) a kind of benign skin growth that is very common among people over 40 years of age. ... Acanthosis nigricans is a brown to black, poorly defined, velvety hyperpigmentation of the skin, usually present in the posterior and lateral folds of the neck, the axilla, groin, umbilicus, and other areas. ... This article is about calluses and corns of human skin. ... Bedsores, more properly termed pressure ulcers, are ulcers (sores) caused by pressure, friction or shear on vulnerable areas of the body, such as bony or cartilaginous areas. ... Lichen sclerosus (LS) (also known as lichen sclerosus et atrophicus (LSA), white-spot disease) is an uncommon disease of unknown cause that results in white patches on the skin, which may cause scarring on and around genital skin. ... Acrodermatitis chronica atrophicans (ACA) also known as Pick-Herxheimer disease, is a skin rash indicative of the third or late stage of European Lyme borreliosis. ... A keloid is a special type of scar which results in an overgrowth of tissue at the site of a healed skin injury. ... Granuloma annulare is a chronic skin disease consisting of a rash with reddish bumps arranged in a circle or ring. ... Necrobiosis lipoidica is a necrotizing skin condition that usually occurs in patients with diabetes. ... Granuloma faciale (GF) is an uncommon benign chronic skin disease of unknown origin characterized by single or multiple cutaneous nodules, usually occurring over the face. ... Her first appearance was in Atari Force #1, Morphea is a DC Comics character who is an alien Canopian in the DC Universe. ... Calcinosis cutis (or cutaneous calcification) is a type of calcinosis wherein calcium deposits form in the skin. ... Sclerodactyly is a localized thickening and tightness of the skin of the fingers or toes. ... Ainhum disease is the autoamputation of the fifth toe. ... In medicine, vasculitis (plural: vasculitides) is a group of diseases featuring inflammation of the wall of blood vessels due to leukocyte migration and resultant damage. ... Livedoid vasculitis (also known as livedo vasculitis, livedo reticularis, and livedoid vasculopathy) is a vascular disorder mostly affecting women. ... Pyogenic granuloma, also referred to as pregnancy tumor, is a primarily oral pathologic condition that appears in the mouth as an overgrowth of tissue due to irritation or trauma. ... // Q00-Q99 - Congenital malformations, deformations and chromosomal abnormalities (Q00-Q07) Congenital malformations of the nervous system (Q00) Anencephaly and similar malformations (Q01) Encephalocele (Q02) Microcephaly (Q03) Congenital hydrocephalus (Q04) Other congenital malformations of brain (Q05) Spina bifida (Q06) Other congenital malformations of spinal cord (Q07) Other congenital malformations of nervous...

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