The visible flakes that fall off of a person's scalp are often referred to as dandruff. Common dandruff is generally caused by an oily scalp. This condition may be exacerbated by the abundance of a certain type of fungus that feeds on the oils on the scalp and hair. Dandruff can also be caused by certain skin disorders, such as psoriasis. Seborrheic dermatitis, however, is one of the most severe types of dandruff, and it can affect other parts of the body besides the scalp.
Dandruff is a scalp disorder in which dead flakes of skin fall off of the scalp. One of the main symptoms of dandruff, besides flaking skin, is an itchy scalp. Although a person's body is always shedding skin, dandruff flakes are usually more visible. They can often be seen on a person's scalp and clothes, as well as in his hair.
Contrary to popular belief, most types of dandruff are not caused by a dry scalp. In fact, they are caused by the opposite problem, an oily scalp. When oil builds up on the scalp, it combines with the dead skin cells and falls off of the scalp. An oil build up on the scalp may be caused by an overproduction of oil or poor personal hygiene.
Too much oil on the scalp also usually leads to another one of the more common types of dandruff. Fungal dandruff is generally caused by a type of fungus known as malassezia. Although this fungus is present on everyone's scalp in small quantities, it can reproduce quickly when a scalp is too oily.
This type of fungus feeds on the oil, which is what makes it able to reproduce so quickly. When the levels of this fungus on the scalp get too high, the scalp becomes irritated. This causes more skin cells to be produced, which causes old skin cells to slough off more quickly. These dead skin cells then combine with the oil on the scalp, creating dandruff flakes.
Not all types of dandruff, however, are caused by oil. Psoriasis is a skin condition in which a person produces too many skin cells too quickly. This causes the skin to shed much faster than normal. Along with other parts of the body, psoriasis can also affect the scalp. Dandruff flakes caused by psoriasis are usually very thick, and they are often silver in color.
Seborrheic dermatitis is a very severe type of dandruff, and like other types of dandruff it also causes the scalp to itch. A person with this type of dandruff will usually have a very red and irritated scalp, and sores will often form. Although seborrheic dermatitis can affect the entire scalp, it is usually more common on the area at the back of the head and neck. In some cases, it may also affect other parts of the body, including the face and ears.