Psoriasis, drugs and habits: A study of 615 patients

Background: psoriasis is a chronic, multifactorial inflammatory disease that affects about 3% of the general population. This disease is thought to be induced or aggravated by several factors, including excessive alcohol intake, physical and psychological stress, and drugs. Several drugs can interfere with psoriasis in predisposed individuals, even if a family history of psoriasis is absent. The more suspected drugs include lithium, β-blockers, antimalarials and nonsteroidal anti-inflammatory drugs (NSAID). The association between alcohol and psoriasis is complex and confusing because many of the initial studies did not control for confounding factors such as tobacco use. Early studies showed no correlation between alcohol consumption and psoriasis. However, as researchers began to control for confounding factors, the results of many studies often showed a significant correlation between alcohol intake and psoriasis. Some studies suggested a relative risk factor of 8.01, particularly in men; these studies did not document an increased risk for psoriasis in women drinking alcohol. Smoking is a risk factor for psoriasis and seems to be associated with the clinical severity of psoriasis. Materials and Methods: we conducted a case-control study to analyse the association between psoriasis and some risk factors for psoriasis, including smoking habits, spirit consumption and drugs. The study was conducted by comparing a group of 615 patients (308 women and 307 men) affected by psoriasis with a group of 900 control subjects (459 women and 441 men). Results: our study shows that smoking constitutes a risk factor in the development of psoriasis. Moreover, we found a dose-response association between smoking and psoriasis. The risk of psoriasis was higher in ex- and current smokers than in non smokers. The relative risk estimates (OR) is 2.6 for ex-smokers and 1.3 for smokers. Our study found an association between smoking and the vulgaris variant of psoriasis but unlike other authors, we did not find any association between smoking and pustular psoriasis. Conclusions: our study confirms the relationship between some drugs and onset/aggravation of psoriasis. Lithium (OR = 5.2), β-blockers and anti-malarials (OR = 3.9), interferons (OR = 3.3), sartans (OR = 3.2) and nonsteroidal antinflammatory drugs (OR = 3.0) were variously associated with a personal history of psoriasis.