Dandruff

Dandruff takes places as the cells of the epidermal layer of the skin continually are pushed outward as they get replaced and these cells eventually die and flake off from the skin. In majority of the persons, these flakes of skin are very small to be seen. However, due to certain conditions, this phenomenon of cell replacement of epidermal layer is unusually rapid in scalp and thereby causing dandruff. Those people that have dandruff, the skin cells get mature and shed in 2–7 days. It is in contrast to other people without dandruff where this process of skin shedding takes about month. This led to the shedding of dead skin cells in large and oily clumps that appear as grey or white patches on the skin, scalp and clothes.

Dandruff is caused by three major factors as shown below.

The Skin oil that is commonly referred to as sebaceous secretions or sebum

The presence of skin microbes and their metabolic by-products

Individual vulnerability

The most specific skin microbe is Malassezia yeasts and as per the common older literature, the fungus Malassezia furfur is the major cause of dandruff. This fungus is naturally found on the surface of the skin in both healthy and infected people. Malassezia globosa is a scalp specific fungus and is regarded as the major responsible agent. This fungus expresses lipase and metabolizes triglycerides that are found in sebum, thus results in a lipid byproduct oleic acid (OA). The penetration by OA in the stratum corneum or the top layer of the epidermis, causes the inflammatory response in suspected persons. It disturbs the homeostasis and causes erratic cleavage of stratum corneum cells.

The dandruff can also be manifested as an allergic reaction to the chemicals contained in hair gels, shampoos, sprays, hair oils, or others. It can also be caused by dandruff medications such as ketoconazole. The excessive perspiration and climate plays a major role in the pathogenesis of dandruff.