Abnormalities of the scalp and hair growth carry a great psychosocial impact, and are intimately related to self-image for both men and women. Hair growth abnormalities include alopecia, hirsuitism, hypertrichosis, seborrheic dermatitis, and psoriasis of the scalp.
Alopecia, known as hair loss, may be further subdivided into diffuse alopecia, in which hair loss occurs throughout the scalp, and focal alopecia, with distinct areas of localized hair loss or bald spots. Another important distinction to be made is whether a scarring or non-scarring process has occurred. In scarring alopecias, inflammation within the scalp leads to destruction of hair follicles.
Hirsuitism is hair growth on women in those parts of the body where hair does not normally occur or is minimal - for example, a beard or chest hair. Hirsuitism is a medical sign rather than a disease and may be an indication of a more serious medical condition, especially if it develops well after puberty. This condition is caused by an increased level of male hormones or an oversensitivity of hair follicles to male hormones.
Hirsuitism is an abnormal amount of hair growth over the body. The two distinct types of hypertrichosis are generalized hypertrichosis, which occurs over the entire body, and localized hypertrichosis, which is restricted to a certain area. Hypertrichosis can be either congenital (present at birth) or acquired later in life.
Seborrheic dermatitis is a common scalp condition that causes scaly, itchy, red skin and stubborn dandruff. In infants, seborrheic dermatitis of the scalp is known as cradle cap. Seborrheic dermatitis can also affect the forehead, brows, cheeks and external ears. While it does not affect your overall health, it can be uncomfortable and cause embarrassment.
PSORIASIS OF THE SCALP
Psoriasis of the scalp may present as one small patch or cover the entire scalp and may also appear on the forehead, on the back of the neck or behind the ears. It presents as reddish patches on the scalp that may be barely noticeable or very noticeable, thick, and inflamed plaques. The scalp may be so dry that the skin cracks and bleeds and dandruff-like flaking and silvery-white scale may be seen. Scratching the scalp to remove the scale can aggravate the problem, known as the Koebner phenomenon. Some hair loss may be seen with thick scaling and plaques; however, once scalp psoriasis clears, hair will often re-grow. Some people have only one mild flare on their scalp, while others have many flare-ups that can range from mild to serious. Many things can trigger a flare-up, including stress, illness, cold weather, dry air and diet.