Hair

There are two common irritations of the scalp that may be associated with temporary hair loss: psoriasis and seborrheic dermatitis, which is commonly known as dandruff.

Two percent of the population have psoriasis at any given time. Its cause is not known, although constitutional factors play an important role, as do other trigger factors. Psoriasis can appear at any time in life. It frequently occurs in adults as sharp-edged scaly red patches on the elbows and knees. It can be more extensive over the trunk and limbs, and can also affect the body folds. Discrete patches can occur on the scalp and occasionally involve the whole scalp. Psoriasis can sometimes be itchy. Tar shampoos can give relief if used on a daily basis, and there are other remedies than are available by prescription, though no permanent cure exists.

Seborrheic dermatitis develops after adolescence. With this condition, the scalp is excessively scaly and greasy, and can be intolerably itchy. Those with greasy coarse-pored skin are more prone to seborrheic dermatitis, and older men are affected more than women. Greasy yellowish scales are found in patches, or are diffuse about the scalp. The skin may be red and inflamed. It may also be present on the hairy areas of the face, on the forehead, or down the broad folds at the side of the nose. Its cause is not fully known, but there is a sensitivity in some people to a naturally occurring, common yeast that overgrows in the scalp skin. Tar shampoo used on a regular basis, or a sulphur-releasing shampoo used intermittently, can be helpful.