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04-11-2010 | Dermatology | Article

Smoking-induced oxidative stress worsens psoriasis


Free abstract

MedWire News: Smoking as a major cause of oxidative stress may play a role in the pathogenesis of psoriasis, researchers report.

The team found that increased intensity and duration of smoking are strongly associated with increasing severity of psoriasis.

"Long-term smoke exposure can result in systemic oxidative stress as reflected by depleted levels of antioxidants," explain E Attwa and E Salem from Zagazig University in Egypt.

"The systemic effects of cigarette smoke are mediated by its role in induction of systemic oxidative stress and inflammation."

The researchers explored the relationship between smoking-induced oxidative stress and clinical severity of psoriasis by measuring malondialdehyde (MDA) and superoxide dismutase (SOD) levels in 25 psoriatic patients (10 smokers, 10 non-smokers, and five ex-smokers) and 20 individuals without the skin condition (10 smokers and 10 non-smokers).

Non-smoking psoriatic patients had significantly increased MDA levels compared with non-smoking healthy individuals, at an average of 4.78 versus 3.4 µmol/l, respectively, and significantly decreased SOD levels, at 1253 versus 1304 U/g hemoglobin (Hb), respectively. These differences between patients and controls were heightened among those who smoked, with average MDA levels of 6.36 versus 3.8 µmol/l, respectively, and average SOD levels of 357.6 versus 1263.1 U/g Hb, respectively.

Attwa and Salem note in the Journal of the European Academy of Dermatology and Venereology that psoriasis was more severe among smokers than non-smokers, with an average Psoriasis Area and Severity Index (PASI) score of 34.36 versus 13.8, respectively, and increased with increasing pack-years of smoking. Also, concentrations of MDA and SOD significantly correlated with PASI score.

However, improvements in MDA and SOD concentrations, as well as PASI score, were seen in ex-smokers compared with smokers.

"Smoking cessation may decrease the degree of smoking-induced inflammation by lowering the level of circulating inflammatory cytokines or restoration of T-cell impairments," say Attwa and Salem.

"Smoking cessation may be an important target for prevention and management of psoriasis."

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Lucy Piper