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 non-smokers). 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.