Psoriasis usually appears during the late teens or twenties, but can occur for the first time at any age.
Men are slightly more prone to psoriasis than women.
The condition usually improves, but may deteriorate with pregnancy.
Emotional stress, injury to the skin (Koebner phenomenon) and certain drugs (lithium, beta blocking agents) may trigger psoriasis.
Withdrawal of systemic cortisone may be associated with the development of generalised pustular psoriasis, and for this reason systemic cortisone is not used routinely to treat psoriasis.
Psoriasis, like most disorders, does not occur equally within different ethnic groups. Up to 5% of Western Europeans have psoriasis, while the condition has not been recorded in Samoa. Unfortunately, we do not have accurate figures for different population groups in New Zealand. It is our impression that the condition is common in European New Zealanders (Pakeha) but is not uncommon amongst Maori.
Alcohol almost certainly does not activate psoriasis (it has however been noted that a significant number of men with severe psoriasis are heavy drinkers).
Many people note that their condition improves in summer and deteriorates in winter. In most cases, however, there is no obvious precipitating or trigger factor.
Interestingly, tonsillitis may activate a variant, known as “Guttate Psoriasis”. “Guttate” means “rain drop” and relates to the small splashes of psoriasis occurring over most of the body. The spots may appear a few days after a sore throat (“Strep Throat”).
Unfortunately, psoriasis may be long-lasting or recurring. It is impossible to predict in any particular individual how long psoriasis will last, or if it will recur.
Guttate psoriasis has the best outlook. Complete disappearance of the condition (over a period of 1 to 54 years) has been reported in 39% of 5355 patients surveyed.