Dandruff

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Dandruff
Dandruff01.jpg
A microscopic image of human dandruff.
Specialty Dermatology
Symptoms Itchy and flaking skin of the scalp[1]
Usual onset Puberty[1]
Causes Genetic and environmental factors[1]
Diagnostic method Based on symptoms[1]
Similar conditions Psoriasis, atopic dermatitis, tinea capitis, rosacea, systemic lupus erythematosus[1]
Medication Antifungal cream (ketoconazole)[1]
Frequency ~50% of adults[1]

Dandruff is a skin condition that affects mainly the scalp.[1] Symptoms include flaking and sometimes mild itchiness.[1] It can result in social or self-esteem problems.[2][1] A more severe form of the condition, which includes inflammation of the skin, is known as seborrheic dermatitis.[1]

The cause is unclear but believed to involve a number of genetic and environmental factors.[1] The condition may worsen in the winter.[3] It is not due to poor hygiene.[4] The underlying mechanism involves the over growth of skin cells.[3] Diagnosis is based on symptoms.[1]

There is no known cure.[5] The typical treatment is with antifungal cream such as ketoconazole.[1] Dandruff affects about half of adults.[1] Onset is usually at puberty.[1] Males are more often affected than females.[1] Rates decrease after the age of 50.[1]

Signs and symptoms[edit]

Severe dryness of scalp resulting in Dandruff.
Typical case of dandruff.

The signs and symptoms of dandruff are an itchy scalp and flakiness.[6] Red and greasy patches of skin and a tingly feeling on the skin are also symptoms.[7]

Causes[edit]

Dandruff can have several causes, including dry skin, seborrhoeic dermatitis, not cleaning/scrubbing often enough, shampooing too often, psoriasis, eczema, sensitivity to hair care products, or a yeast-like fungus.[8] Dry skin is the most common cause of flaking dandruff.[8]

As the skin layers continually replaces itself, cells are pushed outward where they die and flake off. For most individuals, these flakes of skin are too small to be visible. However, certain conditions cause cell turnover to be unusually rapid, especially in the scalp. It is hypothesized that 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 flakes on the scalp, skin and clothes.

According to one study, dandruff has been shown to be possibly the result of three factors:[9]

  1. Skin oil commonly referred to as sebum or sebaceous secretions[10]
  2. The metabolic by-products of skin micro-organisms (most specifically Malassezia yeasts)[11][12][13][14][15]
  3. Individual susceptibility and allergy sensitivity.

Microorganisms[edit]

According to a 2016 study, bacteria (mainly Propionibacterium and Staphylococcus) are more important to dandruff formation than fungi. Bacterial presence was in turn influenced by water and sebum amount.[16]

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, Malassezia globosa,[17] that metabolizes triglycerides present in sebum by the expression of lipase, resulting in a lipid byproduct oleic acid. During dandruff, the levels of Malassezia increase by 1.5 to 2 times its normal level.[3] Oleic acid penetrates the top layer of the epidermis, the stratum corneum, and evokes an inflammatory response in susceptible people which disturbs homeostasis and results in erratic cleavage of stratum corneum cells.[13]

Seborrhoeic dermatitis[edit]

In seborrhoeic dermatitis redness and itching frequently occur around the folds of the nose and eyebrow areas, not just the scalp. Dry, thick, well-defined lesions consisting of large, silvery scales may be traced to the less common affliction of scalp psoriasis. Inflammation can be characterized by redness, heat, pain, swelling and can cause sensitivity.

Inflammation and extension of scaling outside the scalp exclude the diagnosis of dandruff from seborrhoeic dermatitis.[10] 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.[18][19]

Seasonal changes, stress, and immuno-suppression seem to affect seborrheic dermatitis.[3]

Mechanism[edit]

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. A corneocyte is a protein complex that is made of tiny threads of keratin in an organised matrix.[20] 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.[3]

Treatment[edit]

Ketoconazole (Nizoral) shampoo

Shampoos use a combination of special ingredients to control dandruff.

Antifungals[edit]

Antifungal treatments including ketoconazole, zinc pyrithione and selenium disulfide have been found to be effective.[6] Ketoconazole as a shampoo appears to be the most effective.[6]

Ketoconazole is a broad spectrum antimycotic agent that is active against Candida and M. furfur. Of all the antifungals of the imidazole class, ketoconazole has become the leading contender among treatment options because of its effectiveness in treating seborrheic dermatitis as well.[3]

Ciclopirox is widely used as an anti-dandruff agent in most preparations.[21]

Coal tar[edit]

Coal tar causes the skin to shed dead cells from the top layer and slows skin cell growth.[22]

Epidemiology[edit]

Dandruff affects up to half of adults.[6]

Etymology[edit]

According to the Oxford English Dictionary, the word dandruff is first attested in 1545, but is still of unknown etymology.[23]

References[edit]

  1. ^ a b c d e f g h i j k l m n o p q r Borda, Luis (2015). "Seborrheic Dermatitis and Dandruff: A Comprehensive Review". Journal of Clinical and Investigative Dermatology. 3 (2). doi:10.13188/2373-1044.1000019. 
  2. ^ "A Practical Guide to Scalp Disorders". Journal of Investigative Dermatology Symposium Proceedings. 12: 10–14. December 2007. doi:10.1038/sj.jidsymp.5650048. PMID 18004290. 
  3. ^ a b c d e f Ranganathan, S; Mukhopadhyay, T (2010). "Dandruff: the most commercially exploited skin disease". Indian journal of dermatology. 55 (2): 130–4. doi:10.4103/0019-5154.62734. PMC 2887514Freely accessible. PMID 20606879. 
  4. ^ "Dandruff: How to treat". American Academy of Dermatology. Archived from the original on 21 October 2017. Retrieved 20 October 2017. 
  5. ^ Turkington, Carol; Dover, Jeffrey S. (2007). The Encyclopedia of Skin and Skin Disorders (Third ed.). Facts On File, Inc. p. 100. ISBN 0-8160-6403-2. Archived from the original on 2016-05-19. 
  6. ^ a b c d Turner, GA; Hoptroff, M; Harding, CR (Aug 2012). "Stratum corneum dysfunction in dandruff". International Journal of Cosmetic Science. 34 (4): 298–306. doi:10.1111/j.1468-2494.2012.00723.x. PMC 3494381Freely accessible. PMID 22515370. 
  7. ^ "What Is Dandruff? Learn All About Dandruff". Medical News Today. Archived from the original on 2015-08-10. 
  8. ^ a b "Symptoms and causes - Dandruff - Mayo Clinic". www.mayoclinic.org. Archived from the original on 2017-02-02. Retrieved 2017-02-02. 
  9. ^ DeAngelis YM, Gemmer CM, Kaczvinsky JR, Kenneally DC, Schwartz JR, Dawson TL (2005). "Three etiologic facets of dandruff and seborrheic dermatitis: Malassezia fungi, sebaceous lipids, and individual sensitivity". J. Investig. Dermatol. Symp. Proc. 10 (3): 295–7. doi:10.1111/j.1087-0024.2005.10119.x. PMID 16382685. 
  10. ^ a b Ro BI, Dawson TL (2005). "The role of sebaceous gland activity and scalp microfloral metabolism in the etiology of seborrheic dermatitis and dandruff". J. Investig. Dermatol. Symp. Proc. 10 (3): 194–7. doi:10.1111/j.1087-0024.2005.10104.x. PMID 16382662. 
  11. ^ Ashbee HR, Evans EG (2002). "Immunology of Diseases Associated with Malassezia Species". Clin. Microbiol. Rev. 15 (1): 21–57. doi:10.1128/CMR.15.1.21-57.2002. PMC 118058Freely accessible. PMID 11781265. Archived from the original on 2007-10-12. 
  12. ^ Batra R, Boekhout T, Guého E, Cabañes FJ, Dawson TL, Gupta AK (2005). "Malassezia Baillon, emerging clinical yeasts". FEMS Yeast Res. 5 (12): 1101–13. doi:10.1016/j.femsyr.2005.05.006. PMID 16084129. 
  13. ^ a b Dawson TL (2006). "Malassezia and seborrheic dermatitis: etiology and treatment". Journal of cosmetic science. 57 (2): 181–2. PMID 16758556. 
  14. ^ Gemmer CM, DeAngelis YM, Theelen B, Boekhout T, Dawson Jr TL (2002). "Fast, Noninvasive Method for Molecular Detection and Differentiation of Malassezia Yeast Species on Human Skin and Application of the Method to Dandruff Microbiology". J. Clin. Microbiol. 40 (9): 3350–7. doi:10.1128/JCM.40.9.3350-3357.2002. PMC 130704Freely accessible. PMID 12202578. 
  15. ^ Gupta AK, Batra R, Bluhm R, Boekhout T, Dawson TL (2004). "Skin diseases associated with Malassezia species". J. Am. Acad. Dermatol. 51 (5): 785–98. doi:10.1016/j.jaad.2003.12.034. PMID 15523360. 
  16. ^ "Archived copy". Archived from the original on 2016-05-17. Retrieved 2016-05-16. 
  17. ^ "Genetic code of dandruff cracked". BBC News. 2007-11-06. Archived from the original on 2008-12-22. Retrieved 2010-04-30. 
  18. ^ Pierard-Franchimont C, Hermanns JF, Degreef H, Pierard GE (2006). "Revisiting dandruff". Int J Cosmet Sci. 28 (5): 311–318. doi:10.1111/j.1467-2494.2006.00326.x. PMID 18489295. 
  19. ^ Pierard-Franchimont C, Hermanns JF, Degreef H, Pierard GE. From axioms to new insights into dandruff. Dermatology 2000;200:93-8.
  20. ^ Brannon, Heather. "The Structure and Function of the Stratum Corneum". Dermatology.about.com. Archived from the original on 2015-05-24. Retrieved 2017-10-21. 
  21. ^ Milani, M; Antonio Di Molfetta, S; Gramazio, R; Fiorella, C; Frisario, C; Fuzio, E; Marzocca, V; Zurilli, M; Di Turi, G; Felice, G (2003). "Efficacy of betamethasone valerate 0.1% thermophobic foam in seborrhoeic dermatitis of the scalp: An open-label, multicentre, prospective trial on 180 patients". Current Medical Research and Opinion. 19 (4): 342–5. doi:10.1185/030079903125001875. PMID 12841928. 
  22. ^ GENERIC NAME(S): Coal TarFind Lowest Prices (2017-08-16). "''Anti-Dandruff (coal tar)''". WebMD. Archived from the original on 2010-12-12. Retrieved 2017-10-21. 
  23. ^ "dandruff | dandriff, n." OED Online. Oxford University Press, March 2015. Web. Retrieved 27 April 2015.

External links[edit]

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