The appearance of dry, white flakes which fall from your head onto your shoulders and clothes, better known as dandruff, may alarm you. It might appear in combination with an itchy, red skin irritation or sporadically on its own. Nevertheless, most causes of dandruff prove rather harmless and treatable by consistently washing away dead skin cells that collect over time on the scalp.
Dry Skin
Research at the Mayo Clinic suggests that dry skin is the most common cause of dandruff, also called atopic dermatitis. Usually occurring in winter with increased exposure to cold air and heated rooms, dry skin triggers an itching sensation resulting in dead skin to flake off with each subsequent scratch. In contrast to other causes of dandruff, dry skin produces less oily, smaller-sized flakes.
Seborrheic Dermatitis
Overly active sebaceous (oil-producing) glands beneath the skin surface produce skin inflammation often resulting in dandruff. In most cases, the scalp will appear red and greasy, covered with either yellow or white scales. According to an article on the Mass General Hospital for Children website, evidence points to a yeast-like fungus called, malassezia, as the contributing factor of dandruff. Apparently, when the sebaceous gland produces excess oils, the naturally occurring fungus can grow out of control causing scalp-irritation followed by dryness and flaking.
Contact Dermatitis
With contact dermatitis, certain hair products or dyes may irritate the scalp upon contact causing an allergic reaction which can lead to inflammation, itchiness, blistering and dandruff if not rinsed out immediately. Sensitivities vary according to individuals and the length of chemical exposure, where frequent shampooing or extended use of certain styling products may increase the likelihood of irritation.
Excess Dead Skin Cells
Every 28 days, the skin on the scalp renews itself, causing dead skin cells to flake off. In the case of psoriasis, where replacement takes place at a faster rate, such as every four days, the accumulation of dead skin cells can become quite apparent, resulting in the flaking associated with dandruff. Generally, this becomes more significant as the length between hair washing increases, allowing for greater buildup of dead skin cells.
