AskDefine | Define dandruff

Dictionary Definition

dandruff

Noun

1 a condition in which white scales of dead skin are shed by the scalp
2 loose scales shed from the scalp; "I could see the dandruff on her shoulders"

User Contributed Dictionary

English

Alternative spellings

Etymology

The word is first attested in 1545; the first element is obscure, the second element derives from Northumbrian or E. Anglian dialect huff, hurf "scab," from O.N. hrufa, from P.Gmc. *hreufaz, source of O.E. hreofla "leper."

Noun

  1. Scaly white dead skin flakes from the human scalp.
    Dandruff is on my collar again.

Translations

skin flakes

Extensive Definition

Dandruff (also called scurf and historically termed Pityriasis capitis) is due to the excessive shedding of dead skin cells from the scalp. As it is normal for skin cells to die and flake off, a small amount of flaking is normal and in fact quite common. Some people, however, either chronically or as a result of certain triggers, experience an unusually large amount of flaking, which can also be accompanied by redness and irritation. Most cases of dandruff can be easily treated with specialized shampoos. Dandruff is not an organism like lice; it is just dead skin that accumulates in the scalp. Dandruff is unlikely to be the cause of hair loss.
Excessive flaking can also be a symptom of seborrhoeic dermatitis, psoriasis, fungal infection or excoriation associated with infestation of head lice.
Dandruff is a global phenomenon and many people find that dandruff can cause social or self-esteem problems. Treatment may be important purely for psychological reasons.

Causes

As the epidermal layer continually replaces itself, cells are pushed outward where they eventually die and flake off. In most people, these flakes of skin are too small to be visible. However, certain conditions cause cell turnover to be unusually rapid, especially in the scalp. For people with dandruff, skin cells may mature and be shed in 2 - 7 days, as opposed to around a month in people without dandruff. The result is that dead skin cells are shed in large, oily clumps, which appear as white or grayish patches on the scalp, skin, and clothes.
Dandruff has been shown to be the result of three required factors:
  1. Skin oil commonly referred to as sebum or sebaceous secretions
  2. The metabolic by-products of skin micro-organisms (most specifically Malassezia yeasts)
  3. Individual susceptibility
Common older literature cites the fungus Malassezia furfur (previously known as Pityrosporum ovale) as the cause of dandruff. While this fungus is found naturally on the skin surface of both healthy people and those with dandruff, it was discovered that a scalp specific fungus, Malassezia globosa, is the responsible agent. This fungus metabolizes triglycerides present in sebum by the expression of lipase, resulting in a lipid byproduct oleic acid (OA). Penetration by OA of the top layer of the epidermis, the stratum corneum, results in an inflammatory response in susceptible persons which disturbs homeostasis and results in erratic cleavage of stratum corneum cells. However, elimination of the fungus results in dramatic improvement. Regular shampooing with an anti-fungal product can reduce recurrence.
Anti-fungal/anti-dandruff shampoos containing ketoconazole have been shown to be more effective than zinc pyrithione. Ketoconazole is the most effective antifungal agent according to one study.

See also

References

dandruff in Catalan: Caspa
dandruff in Czech: Lupy
dandruff in German: Hautschuppe
dandruff in Spanish: caspa
dandruff in French: Pellicule (dermatologie)
dandruff in Korean: 비듬
dandruff in Indonesian: Ketombe
dandruff in Icelandic: Flasa
dandruff in Italian: Forfora
dandruff in Dutch: Hoofdroos
dandruff in Japanese: 頭垢
dandruff in Polish: Łupież
dandruff in Portuguese: Dermatite seborréica
dandruff in Romanian: Mătreaţă
dandruff in Russian: Перхоть
dandruff in Finnish: Hilse
dandruff in Swedish: Mjäll
dandruff in Vietnamese: Gàu (da đầu)
dandruff in Turkish: Kepek
dandruff in Chinese: 头皮屑

Synonyms, Antonyms and Related Words

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