Relationship between smoking-induced oxidative stress and the clinical severity of psoriasis

Background Psoriasis is a chronic and recurrent inflammatory skin disease, known as an oxidative stress condition. Smoking augments the risk of development of psoriasis. Although the relative importance of potential mechanisms of smoking-induced psoriasis is unknown, direct delivery of oxidants has been implicated in the pathogenesis of smoking-induced psoriasis. Objectives This study aimed to investigate the smoking-induced oxidative stress in psoriatic patients and its correlation with the severity of the disease. Methods The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured in 25 psoriatic patients (10 smokers, 10 non-smokers and 5 ex-smokers) and 20 healthy control subjects (10 smokers and 10 nonsmokers). Clinical severity of psoriasis was determined according to the Psoriasis Area Severity Index (PASI) score. Results Our results showed a significant increase in serum MDA and decrease in the blood SOD levels in psoriatic patients compared with those in control subjects and those in smokers compared with those in non-smokers. The concentrations of MDA and SOD were significantly correlated with PASI score. There was a significant increase in PASI score in smoker patients compared with that in non-smokers and it increased with increasing the pack-years of smoking. Conclusions Our results indicate that smoking-induced oxidative damage resulting from increased reactive oxygen species production along with insufficient capacity of antioxidant mechanisms may be involved in the pathogenesis of psoriasis.