NEW YORK (Reuters Health) - There is no evidence that probiotics can relieve the bothersome symptoms of eczema and there is some evidence that they may occasionally cause infections and gut problems, conclude researchers based on a review of the best available research on the topic.

Eczema is an itchy red skin rash that affects up to 20 percent of children, Dr. Robert John Boyle of the Royal Children's Hospital in Parkville, Victoria, Australia and colleagues note in The Cochrane Library, a publication of the Cochrane Collaboration, an international organization that evaluates medical research.

Studies have shown that the guts of people with eczema have a different bacterial environment than those who don't have the condition, raising the possibility that changing this environment by administering probiotics or "good" bacteria could help treat the disease. While some doctors now recommend probiotics for eczema, the treatment is controversial, and there is evidence that it can lead to harmful side effects.

To investigate, Boyle and colleagues reviewed 12 randomized controlled trials comparing probiotics to placebo in 781 children with eczema.

The quality of the studies was mixed, the researchers report, and overall analysis suggested that probiotics were not effective. No significant reduction in disease severity or improvements in quality of life were seen, while no study showed reductions in absenteeism from school or work. Though a beneficial effect of the treatments studied couldn't be ruled out, they add, it "is likely to be modest."

Many studies did not provide information on side effects, but among the minority that did give this information, the researchers found no significant difference between the groups given probiotics and those given placebo.

"Probiotic treatment is generally safe, however it can lead to adverse events including sepsis and bowel ischaemia -- the precise risk of such events is difficult to quantify, but is likely to be very low for most people," Boyle and his team write.

In a written statement accompanying the report, Boyle concludes: "Further probiotic eczema treatment studies would help to clarify whether specific probiotic strains have a greater effect on eczema severity and symptoms than the strains studied to date, and might evaluate their efficacy in adolescent/adult populations."

SOURCE: The Cochrane Library 2008.