Introduction
The skin and scalp can be divided into different layers, from the inside to the outside it is roughly divided into the dermis and epidermis. The outermost layer is a special horny layer of keratinized cells, which forms a barrier to the outside. Approximately every four weeks there is usually a complete renewal of the horny layer of the scalp.
Therefore, every person loses small skin scales every day, but these are so small that they cannot be seen with the naked eye. These are old, dead skin cells that have been replaced by new skin cells during the renewal process. In order to protect the scalp, it is normally covered with a fine film of fat.
This is formed by the sebaceous glands, which lie in the dermis of the scalp. The fat film binds the moisture on the scalp, prevents its evaporation and thus protects the scalp from dryness. However, sebum production is different in each person and therefore determines the respective skin type.
A distinction can be made between an oily skin type (seborrhea) and a dry skin type (sebostasis) as well as a mixed type. The skin type is innate and does not normally change, but it can be influenced by external factors. In our uppermost skin layer there are certain substances that are supposed to maintain the skin’s moisture.
These include urea, for example, which gets there through sweat and is also found in many creams and shampoos. Healthy skin contains about three times as much urea as skin that is too dry. In the course of the aging process it is normal that the sebum production and also the urea concentration decreases and therefore with increasing age a drier skin develops.
In babies and toddlers, the activity of the sebaceous glands is only minimally pronounced, so they lack an important protection against dry skin. They are therefore more sensitive and also more susceptible to dry scalp. If the scalp is irritated, there is an increased production of skin cells in the short term until the scalp recovers.
The newly formed scalp cells displace the damaged cells and there is increased exfoliation of skin cells. These clump together and form large, white scales that can be seen with the naked eye, especially at the hairline, neck and shoulder area. The formation of dandruff occurs mainly between the ages of 20 and 49 years.
The formation of dandruff can have different causes and can also look different depending on the disease. If the skin is too dry, white, dry scales appear, which typically trickle down from the hair. However, dandruff formation is not only possible in the context of a dry scalp.
Also with too oily skin, dandruff can form, but then yellowish and oily and stick to the hair. For example, a fungal attack of the scalp with the fungus Malassezia furfur, which feeds on the secreted, oily sebum. The fungus occurs on the scalp of every person, but if the scalp tends to produce too much sebum, the fungus can multiply quickly. It comes to the formation of the typical oily scales. In addition, there is often a strong itching.
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