Dandruff is simply dead skin shedding from your head at a fast rate. Almost everyone has had dandruff at some point to one degree or another. People with a strong degree of dandruff will experience an itchy scalp.
Causes
Skin cells that grow and die off too fast are the cause of dandruff, but doctors do not know why this happens. Some people with severe flaking have overactive sebaceous glands (whose task is to lubricate the skin with oils); others have an elevated level of the fungus Pityrosporum ovale, which is present in most people but it is in excess in people with the problem of dandruff. Other factors include family history, food allergies, excessive sweating, use of alkaline soaps, yeast infections and stress. Even the season of the year can contribute to the problem: Cold, dry winters are notorious for bringing on dandruff or making it worse.
If dandruff flakes are greasy and yellow, the probable cause is the skin condition known as seborrheic dermatitis; seborrhea is usually associated with redness as well. Dry, thick lesions consisting of large, silvery scales may be traced to the less common psoriasis of the scalp. These forms of dandruff -- as well as the run-of-the-mill variety - become a hazard only if you scratch to the point of causing breaks in the skin, which can place you at greater risk for infections, particularly from staph and strep bacteria
Treatment
Many over-the-counter shampoos can keep moderate dandruff in check, but consult your doctor about more stubborn forms such as seborrheic dermatitis. Some herbal remedies may relieve the itching and dryness, but it usually takes a medicated product to subdue the greasy scales.
