Costly silver dressings should not be routinely used on wounds until there is better evidence to support their use, say UK researchers.
But some experts insist silver dressings are an essential tool in treating burn wounds.
An evaluation published today in the Drug and Therapeutics Bulletin concludes that the UK National Health Service expenditure on silver dressings is "difficult to justify in the light of existing data".
"Silver dressings are expensive and there have been few high-quality clinical trials to establish whether they have advantages over other, cheaper, alternatives," says the Bulletin.
"Most of the studies that have been conducted have had considerable methodological limitations."
The Bulletin says routine use of silver dressings is not justified on clinical or cost-effectiveness grounds as treatment for uncomplicated leg ulcers. It says simple dressings and compression bandaging are more appropriate for this.
It also says silver dressings should not be used on acute wounds as there weak evidence to suggest that they delay wound healing.
"There is a better case for using silver dressings for patients with infected burns, but even here, the evidence base is weak," concludes the Bulletin.
The evaluation also discusses the potential for patients to experience hypersensitivity or toxicity due to absorption of silver, and the possibility of dressings contributing to the development of resistant microbes.
New Zealand-based clinical epidemiologist, Dr Andrew Jull of the University of Auckland who is an editor of the Cochrane Wounds Group agrees with the evaluation.
"This is a well reasoned description of the evidence base for silver dressings," says Jull.
"Silver is anti-bacterial in bench-top terms but when it comes to real patients, the quality of evidence is very low."
He believes silver dressings should not be used routinely in leg ulcers and diabetic foot ulcers.
"In other scenarios, I would always say it's a second choice, not a first-line treatment," says Jull.
He says the destruction of skin in serious burns provides greater justification for using silver dressings, but wonders whether antibiotics may be more effective.
Silver dressings defended
But some doctors defend their use of silver dressings to prevent the infection of burn wounds and potentially-lethal toxic shock syndrome.
"The vast majority of burns surgeons in Australia use silver dressings," says Professor Roy Kimble of the University of Queensland in Brisbane, who is also director of burns and trauma at the Royal Children Hospital in Brisbane.
"I'd say that we do have enough evidence to say what we're doing is sound and ethical."
Kimble says there has been an explosion of silver dressings on the market and he agrees many of them have not been properly tested.
But he says he has been involved in a number of studies on the nano-crystalline silver dressing used by most burn units in Australia.
"It's a special silver lattice, which you add water to and it releases silver atom ions and silver atoms. Silver ions kill bacteria and silver atoms almost certainly work as an anti-inflammatory. Both of which are very good for burn wound healing," says Kimble.
"We know that using silver dressings decrease the amount of burn wound infection."
He also says silver dressings are cost effective because they don't have to be changed as often as other dressings.
Kimble says given the available evidence it would be "unethical" to carry out randomised control studies comparing silver dressings to non-antimicrobial dressings.
"I know that I'd be increasing the wound infection rate so I'm not going to do that study," he says.