Dandruff Classification and external resources
A microscopic image of human dandruff
ICD-9 690.18 DiseasesDB 11911
Dandruff (Latin: Pityriasis simplex capillitii) is the shedding of dead skin cells from the scalp (not to be confused with a dry scalp). Dandruff is sometimes caused by frequent exposure to extreme heat and cold. As it is normal for skin cells to die and flake off, a small amount of flaking is normal and common; about 487,000 cells/cm2 get released normally after detergent treatment. Some people, however, either chronically or as a result of certain triggers, experience an unusually large amount of flaking, up to 800,000 cells/cm2, which can also be accompanied by redness and irritation. Most cases of dandruff can be easily treated with specialized shampoos.
Dandruff is a common scalp disorder affecting almost half of the population at the pre-pubertal age and of any sex and ethnicity. In some cultures dandruff is considered aesthetically displeasing. It often causes itching. It has been well established that keratinocytes play a key role in the expression and generation of immunological reactions during dandruff formation. The severity of dandruff may fluctuate with season as it often worsens in winter.
Those affected by dandruff find that it can cause social or self-esteem problems. Treatment may be important for both physiological and psychological reasons.
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:
- Skin oil commonly referred to as sebum or sebaceous secretions
- The metabolic by-products of skin micro-organisms (most specifically Malassezia yeasts)
- Individual susceptibility
Older literature cites the fungus Malassezia furfur (previously known as Pityrosporum ovale) as the cause of dandruff. While this species does occur naturally on the skin surface of both healthy people and those with dandruff, in 2007 it was discovered that the responsible agent is a scalp specific fungus. During dandruff, the levels of Malassezia increase by 1.5 to 2 times its normal level. Malassezia globosa, that 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.
Dandruff scale is a cluster of corneocytes, which have retained a large degree of cohesion with one another and detach as such from the surface of the stratum corneum. The size and abundance of scales are heterogeneous from one site to another and over time. Parakeratotic cells often make up part of dandruff. Their numbers are related to the severity of the clinical manifestations, which may also be influenced by seborrhea.
Flaking is a symptom of seborrhoeic dermatitis. Joseph Bark notes that "Redness and itching is actually seborrheic dermatitis, and it frequently occurs around the folds of the nose and the eyebrow areas, not just the scalp." Dry, thick, well-defined lesions consisting of large, silvery scales may be traced to the less common psoriasis of the scalp.
The spectrum of dandruff is difficult to define because it blurs with seborrhoeic dermatitis and some other scaly conditions. The inflammation and extension of scaling outside the scalp exclude the diagnosis of dandruff from seborrhoeic dermatitis. However, many reports suggest a clear link between the two clinical entities - the mildest form of the clinical presentation of seborrhoeic dermatitis as dandruff, where the inflammation is minimal and remain subclinical. Histological examination reveals the scattered presence of lymphoid cells and squirting capillaries in the papillary dermis with hints of spongiosis and focal parakeratosis.
Seasonal changes, stress, and immuno-suppression seem to affect seborrheic dermatitis.
Coconut Oil use a combination of ingredients to control dandruff. The pathogenesis of dandruff involves hyperproliferation of keratinocytes, resulting in deregulation of keratinization. The corneocytes clump together, manifesting as large flakes of skin. Essentially, keratolytic agents such as salicylic acid and sulphur loosen the attachments between the corneocytes and allow them to get swiped off.
Regulators of keratinization
Zinc pyrithione (ZPT) heals the scalp by normalizing the epithelial keratinization or sebum production or both. Some studies have shown a significant reduction in the number of yeasts after use of ZPT, which is an antifungal and antibacterial agent. A study by Warner et al. demonstrates a dramatic reduction of structural abnormalities found in dandruff with the use of ZPT; the population abundance of Malassezia decreases, parakeratosis gets eliminated and corneocytes lipid inclusions are diminished.
The parakeratotic properties of topical corticosteroids depend on the structure of the agent, the vehicle and the skin onto which it is used. Corticosteroids work via their anti-inflammatory and antiproliferative effects.
It is believed that selenium sulfide controls dandruff via its anti Malassezia effect rather than by its antiproliferative effect, although it has an effect in reducing cell turnover. It has anti-seborrheic properties as well as cytostatic effect on cells of the epidermal and follicular epithelium. The excessive oiliness after use of this agent has been reported in many patients as adverse drug effec
Imidazole antifungal agents
Imidazole topical antifungals such as ketoconazole act by blocking the biosynthesis of ergosterol, the primary sterol derivative of the fungal cell membrane. Changes in membrane permeability caused by ergosterol depletion are incompatible with fungal growth and survival.
Ketoconazole is a broad spectrum, antimycotic agent that is active against both Candida and M. furfur . Of all the imidazoles, ketoconazole has become the leading contender among treatment options because of its effectiveness in treating seborrheic dermatitis as well.
In contrast to the imidazole antifungals, the hydroxypyridones do not affect sterol biosynthesis; instead they interfere with the active transport of essential macromolecule precursor, cell membrane integrity and the respiratory process of cells. Ciclopirox is widely used as an AD agent in most preparations.
Like other skin conditions, hot water can exacerbate dandruff or itching. Using slightly cooler water (not cold) during regular hair washing and rinsing has been found to reduce dandruff in some individuals.
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Dermatitis and eczema (L20–L30, 690–693,698) Atopic dermatitisBesnier's prurigo Seborrheic dermatitisPityriasis simplex capillitii · Cradle cap Contact dermatitis
EczemaAutoimmune estrogen dermatitis · Autoimmune progesterone dermatitisBreast eczema · Ear eczema · Eyelid dermatitis · Hand eczema (Chronic vesiculobullous hand eczema, Hyperkeratotic hand dermatitis) Pruritus/Itch/
Prurigoby location: Pruritus ani · Pruritus scroti · Pruritus vulvae · Scalp pruritusDrug-induced pruritus (Hydroxyethyl starch-induced pruritus) · Senile pruritus · Aquagenic pruritus (Aquadynia)Adult blaschkitis · due to liver disease (Biliary pruritus · Cholestatic pruritus) · Prion pruritus · Prurigo pigmentosa · Prurigo simplex · Puncta pruritica · Uremic pruritus
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Look at other dictionaries:
Dandruff — (d[a^]n dr[u^]f), n. [Prob. from W. toncrust, peel, skin + AS. dr[=o]f dirty, draffy, or W. drwg bad: cf. AS. tan a letter, an eruption. [root]240.] A scurf which forms on the head, and comes off in small scales or particles. [Written also… … The Collaborative International Dictionary of English
dandruff — (n.) 1540s, first element obscure, second element is Northumbrian or E. Anglian dialectal huff, hurf scab, from O.N. hrufa, from P.Gmc. *hreufaz, source of O.E. hreofla leper … Etymology dictionary
dandruff — [n] scurf flakes, seborrhea; concept 831 … New thesaurus
dandruff — ► NOUN ▪ flakes of dead skin on a person s scalp and in the hair. ORIGIN origin uncertain … English terms dictionary
dandruff — [dan′drəf] n. [< earlier dandro, dander ( < ?) + dial. hurf, scab < ON hrufa: see GRAUPEL] 1. little scales or flakes of dead skin formed on the scalp 2. a condition of the scalp in which such scales are formed dandruffy adj … English World dictionary
Dandruff — A mild skin condition that produces white flakes that may be shed and fall from the hair. Dandruff is due to the sebaceous glands overworking. (The sebaceous glands keep the skin properly oiled.) Another cause of dandruff is fungus, especially… … Medical dictionary
dandruff — [[t]dæ̱ndrʌf[/t]] N UNCOUNT Dandruff is small white pieces of dead skin in someone s hair, or fallen from someone s hair. He has very bad dandruff … English dictionary
dandruff — dandruffy, dandriffy, adj. /dan dreuhf/, n. a seborrheic scurf that forms on the scalp and comes off in small scales. Also, dandriff /dan drif/. [1535 45; orig. uncert.] * * * Skin disorder of the scalp, a mild form of dermatitis. It affects most … Universalium
dandruff — noun Scaly white dead skin flakes from the human scalp; Pityriasis capitis. Dandruff is on my collar again … Wiktionary
dandruff — noun Dandruff is used before these nouns: ↑shampoo … Collocations dictionary