Some of the most common causes for an itchy scalp include eczema, scalp psoriasis and seborrheic dermatitis. This third cause is also known as dandruff, but those flakes are merely a cosmetic issue that does not require medical treatment, as stated by WebMD.
Seborrheic dermatitis leads to redness, flaking and itching, and it can show up in multiple places on the body. Called dandruff when it hits the scalp, this is treatable with shampoos available over the counter that contain medicine to control the flakes. People with dandruff that these shampoos do not help can get prescription shampoos and creams with steroids to address the issue, notes WebMD.
Scalp psoriasis also leads to flaking and itching on the scalp. Psoriasis results when the body's immune system causes excess skin cells to grow all over the body, including the scalp. Eczema is most frequent in infants and children, but anyone can develop it. No one knows what causes eczema, but the symptoms are treatable with prescription steroid creams and moisturizers. Avoiding stress and disciplining oneself not to scratch also ease the itching. Parkinson's disease and HIV patients both have higher instances of dandruff, although the cause remains unknown, according to WebMD.