Dandruff

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. Simple dandruff does not cause 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 can be important for purely social 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 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. an 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 has recently been shown that a scalp specific fungus, Malassezi 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 which disturbs homeostasis and results in erratic cleavage of straum corneum cells.

Rarely, dandruff can be a manifestation of an allergic reaction to chemicals in hair gels/sprays, hair oils, or sometimes even dandruff medications like Ketoconazole.

There is no convincing evidence that food (such as sugar or yeast), excessive perspiration, or climate have any role in the pathogenesis of dandruff.

There have been many strategies for the control of dandruff. Simply increasing shampooing will remove flakes. However, elimination of the fungus results in dramatic improvement. Regular shampooing with an anti-fungal product will not only treat but prevent recurrence.

Seborrheic dermatitis

Flaking is a symptom of seborrheic 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.

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

Treatment

Severe forms of flaking if accompanied by flaking or scaling on other parts of the body, might best be treated by a dermatologist.
Head & Shoulders anti-dandruff shampoo containing active ingredient Zinc pyrithione. ^{[citation needed]}
Nizoral Shampoo anti-fungal/anti-dandruff shampoo containing active ingredient Ketoconazole.
Selsun Blue anti-dandruff shampoo containing active ingredient Selenium sulfide.
The antifungal properties of Tea Tree Oil (Melaleuca Oil) have been reported as useful in the treatment of dandruff. [1] [2] [3]
Washing hair with rubbing alcohol gets rid of the dandruff and leaves hair feeling soft and clean. ^{[citation needed]}
Tar containing shampoos are also used for treatment of dandruff. [4]
Apple Cider Vinegar helps destroy the bacteria that causes Dandruff thus, eliminating your dandruff. ^{[citation needed]}
Sitting next to Alex Logan can not help...

Misconceptions

Dandruff is sometimes confused with dried shampoo. This usually occurs when hair isn't rinsed properly.
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.

References

Margen, Sheldon, M.D. "Wellnessfoods A to Z." Rebus Press, ISBN 0-929661-70-2
Thomas L. Dawson Jr. (2006) Malassezia and seborrheic dermatitis: etiology and treatment. J Cosmet Sci. 57(2):181-2.
Roma Batra, Teun Boekhout, Eveline Guého, F. Javier Cabañes, Thomas L. Dawson, Jr., and Aditya K. Gupta (2005) Malassezia Baillon, emerging clinical yeasts. FEMS Yeast Research 5:1101-1103.
Yvonne M. DeAngelis, Christina M. Gemmer, Joseph R. Kaczvinsky, Dianna Kenneally, James Schwartz, and Thomas L. Dawson, Jr. (2005) Three etiologic facets of dandruff and seborrheic dermatitis: Malassezia fungi, Sebaceous lipids, and Individual sensitivity. J Invest Dermatol. Symp Proc 10:295-297.
Byung In Ro, and Thomas L. Dawson, Jr. (2005) The Role of Sebaceous Gland Activity and Scalp Microfloral Metabolism in the Etiology of Common Scalp Conditions. J Invest Dermatol. Symp Proc 10:194 –197.
Aditya K Gupta, Roma Batra, Robyn Bluhm HBSc, Teun Boekhout, and Thomas L. Dawson, Jr. (2004) Skin diseases associated with Malassezia species. J Am Acad Dermatol 51:785-98.
Gemmer, Christina, Yvonne DeAngelis, Bart Theelen, Teun Boekhout, and Thomas L. Dawson, Jr (2002) A fast, non-invasive method for identification and speciation of Malassezia, and it application to dandruff biology. J. Clin. Micro., 40 (9): 3350-3357.
Warner, R., Ying Boissy, James R. Schwartz, and Thomas L. Dawson, Jr (2001) Dandruff has an altered stratum corneum ultrastructure that is improved with Zinc Pyrithione shampoo. JAAD, 45 (6-1): 897-903.
Ashbee HR, Evans EG. Immunology of diseases associated with Malassezia species. Clin Microbiol Rev 2002;15:21-57.
Bulmer AC, Bulmer GS. The antifungal action of dandruff shampoos. Mycopathologia 1999;147:63-5.
Kligman AM. Perspectives and problems in cutaneous gerontology. J Invest Dermatol 1979;73:39-46.
McGrath J, Murphy GM. The control of seborrhoeic dermatitis and dandruff by antipityrosporal drugs. Drugs 1991;41:178-84.
Pierard-Franchimont C, Hermanns JF, Degreef H, Pierard GE. From axioms to new insights into dandruff. Dermatology 2000;200:93-8.
Priestley GC, Savin JA. The microbiology of dandruff. Br J Dermatol 1976;94:469-71.
Faergemann J. Seborrheic Dermatits (Dandruff). New York: Marcel Dekker, Inc.; 2000. p. 197-202.
Shuster S. The aetiology of dandruff and the mode of action of therapeutic agents. Br J Dermatol 1984;111:235-42.