psoriasis

Definition – psoriasis is a chronic inflammatory skin condition,
characterised by localised, widespread well-demarcated red plaques often
topped by silvery scales. In 10 per cent of cases psoriasis is associated wit
degree of arthritis.
Distribution – areas most commonly affected are the elbows, knees and
scalp. The disease often persists throughout life, frequently displaying a
tendency for improvement in the summer.
Prevalence – psoriasis affects approximately 2 per cent of the population
Europe and North America but may be less common in Africa and Japan
Males and females are affected equally. Onset can occur at any age, but is
most common in the second and third decades of life. It rarely occurs in
children under 8 years of age. A tendency for family members to also hav
the condition has been noted in around 40 per cent of cases.
Cause – although the exact cause of psoriasis is not fully understood, the
basic abnormality is thought to be immunologically based, perhaps
autoimmune, and is associated with an enlarged population of certain sk
cells that divide too rapidly.
Treatment – the selected treatment depends upon the degree of rash, the
site of the lesions and the pattern of distribution. Thus mild forms of the
condition tend to be treated with topical steroid creams in more severe ca
this therapy is supported by other topical treatments such as tar-based
compounds. In severe cases, topical therapy may be combined with
phototherapy or PUVA, or with oral immunosuppressive therapy.