Interaction between selenium and arsenic in biological samples of psoriasis patients.

Background: Psoriasis is a noncontagious, chronic skin disease affecting 1 in 50 people worldwide.

Methods: The aim of present study was to compare the levels of arsenic (As) and selenium (Se) in samples of whole blood, urine, and scalp hair of 418 psoriasis patients of both genders aged 25 - 55 years. All psoriatic patients lived in the vicinity of a cement factory, and were categorized as mild, moderate, and severe. For comparison purposes, 395 healthy age-matched referent/control subjects, residents of industrial and non-industrial areas, were selected. The concentrations of essential trace and toxic elements were measured by electrothermal atomic absorption spectroscopy after microwave-assisted acid digestion. The validity and accuracy of methodology was checked by using certified reference materials (CRMs) and the conventional wet acid digestion method on the same CRMs and real samples.

Results: The observed mean values of As were significantly higher in scalp hair, blood, and urine samples of patients with mild and severe psoriasis as compared to the controls (p = 0.01 - 0.001), while the concentrations of Se were lower in the scalp hair and blood, but higher in the urine samples of psoriasis patients of all categories.

Conclusions: The deficiency of Se in psoriatic patients may undoubtedly be caused by the toxic element exposures via dust produced by the cement factory.