Psoriasis may affect up to 2% of the world’s population. Psoriasis has a genetic component and it seems Caucasians are the most susceptible ethnic group. The development of psoriasis may occur at any age, but the most common age for it to begin is when people are in their mid thirties. It is another inflammatory skin condition that involves a suspected autoimmune disease mechanism. The exact cause is unknown, but it has been shown that onset may be preceded by streptococcal infection or stress in some cases.
Clinically, the scalp is often involved with psoriasis plaques especially for children and teenagers. Psoriasis most frequently looks like a bright pink patch that is covered in small scales of dead skin. In severe cases the entire scalp can be affected and the scale builds up and forms a sort of cap that can be seen all over the scalp and may also cover non-hairy areas like the forehead. Sometimes people with psoriasis are also be susceptible to the development of seborrheic dermatitis. This may later turn into psoriasis.
As well as directly affecting the skin, psoriasis may also indirectly cause noticeable hair loss if it develops in hair bearing skin such as the scalp. The psoriasis plaques (affected patches of skin) may contain hair follicles that have been forced into the telogen resting stage by the condition and this results in few visible hairs being present in the psoriasis plaques. This telogen effluvium is the typical form of hair loss that psoriasis induces, but sometimes psoriasis can cause a scarring alopecia. While psoriasis induced telogen effluvium is fully reversible with successful treatment, the psoriasis induced scarring alopecia is a permanent form of hair loss.
Psoriasis cannot be cured, but there are treatments to help control it. For mild examples of psoriasis a tar shampoo may be all that is required. More extensive psoriasis may be treated with a shampoo containing dithranol. If the inflammation is significant the dermatologist may use a corticosteroid to control it. The corticosteroid treatment may involve topical creams or sometimes local corticosteroid injections into the skin are used. Recently, preparations containing calcipotroil have been shown to be very useful in treating scalp psoriasis.