Bath products are an effective way of managing eczema in children, new NHS guidelines say, despite a recent report saying such emollients may do little.
Allergic eczema affects children more than adults
But the NHS watchdog warns parents not to waste money on "high street" allergy tests for the condition, and to avoid herbal remedies and food supplements.
The efficacy of these is unproven, and they may cause side-effects, it says.
This is the first time recommendations for treating eczema, which affects one in five children, have been compiled.
The National Institute for Health and Clinical Excellence (NICE) urges a "holistic" approach which considers the child's psychological as well as physical condition.
Eczema - inflammatory skin disorders that make the skin dry, itchy, flaky, red and sore - can have a distressing impact on the entire family, it notes.
It can affect a child's self-esteem and confidence, and sleep disturbance due to itchy skin can keep the whole household up.
The new guidelines urge doctors to work out if there is anything which sparks the eczema, such as soaps or certain foods, and says time should be taken to discuss the condition with the child and carers.
In addition to topical steroid creams, they also recommend that patients are offered a choice of emollients for moisturising, washing and bathing.
This recommendation comes despite a report in the October edition of Drug and Therapeutics Bulletin, a respected journal providing independent reviews of medication, suggesting there was no evidence bath emollients were effective.
Bath emollients are thought to be an easier way of applying the treatment to a large skin surface area and they are also thought to trap moisture into the skin.
But the researchers said there was no clinical evidence that they did this, and that they may even have undesirable effects, such as accidents caused by a slippery bath.
They calculated that the NHS spent £16m per year on the products, which can cost as much as 70p per bath.
"We have seen nothing to change our minds on this and we would still question the basis for using them," said the journal's editor, Ike Iheanacho.
"Unfortunately there is no incentive for drug companies to carry out clinical trials when so many organisations - now including NICE - are prepared to accept that they work despite the lack of evidence."
The National Eczema Society, which criticised the report at the time, said it wholeheartedly welcomed the new guidelines.
"We hope that the guidelines will help healthcare professionals to encourage discussion of the various treatment options and to make them available as well as to understand the importance of discussing psychological factors," said its head, Margaret Cox.
She urged NICE to develop similar guidelines for the treatment of adult eczema, although the condition is much more common in children.