Excess Scalp Oil
Dandruff on your scalp is caused by an organism called pityrosporum-ovle. According to Anti-dandruff.com, modest amounts of this organism exist on everyone's scalp. Excessive amounts of oil in your scalp can cause pityrosporum-ovle to multiply, resulting in the white, dry flakes commonly known as dandruff. More severe cases are known as seborrheic dermatitis, characterized by dry, flaky and red scales on your scalp.
People who have dandruff associated with an oily scalp typically think that their scalp is dry, and that the problem is solved by skipping shampoo sessions. However, such action makes dandruff worse when excessive oil is to blame. It is generally recommended that people wash their hair every other day. If you still see signs of dandruff, you may consider shampooing daily with an anti-dandruff shampoo. Selsun Blue is effective for seborrheic dermatitis, and you can use it up to three times a week. See your doctor for a prescription shampoo if your condition does not improve.
Lifestyle
Although excessive scalp oil is a common trigger for hair dandruff, certain lifestyle choices may also be to blame. If you have sensitive skin, you likely avoid harsh chemical-based products, and you should do the same with hair products. Shampoos, conditioners, styling products and hair dyes can irritate your scalp, resulting in the multiplication of pityrosporum-ovle and dandruff. This condition is called contact dermatitis. In some cases, the problem is solved by reducing the application of such products. If you are particularly sensitive, however, your best bet is to skip irritating hair products all together.
You must shampoo regularly, regardless of your skin type. Dry scalps will actually benefit from a moisturizing dandruff shampoo. Good hair hygiene will help keep dandruff at bay.
Other Causes
Allergies can cause dandruff on your scalp. According to Mayo Clinic, eczema is a common culprit of hair dandruff. Eczema is similar in appearance to sebborheic dermatitis, but is not as widespread. If you have food allergies, you can develop seborrheic dermatitis, causing the flakes.
If you have seasonal allergies, you may be more prone to dandruff during certain times of the year in which you experience other symptoms. Some people tend to develop dandruff during winter, as your pores excrete more oils in order to lubricate your skin and scalp in response to drier conditions.
Psoriasis is another condition that can cause dandruff. Psoriasis differs in appearance from eczema and seborrheic dermatitis in that the dry scales are silver in color. The accumulation of scales results in their eventual shedding.
