Vaseline – which is cheaper than moisturizer – can protect skin against eczema, a new study shows.

Eczema impacts as many as 20 percent of children and costs the U.S. healthcare system as much as $3.8 billion dollars every year.

Previous studies have shown that families caring for a child with the costly skin disorder can spend as much as 35 percent of their discretionary income -- an average of $274 per month.

According to Northwestern Medicine researchers in Chicago, Ill., seven moisturizers are cost-effective in preventing eczema, a costly, inflammatory skin disorder that afflicts newborns.

They found that seven common moisturizers are cost-effective in protecting a baby’s skin, including applying Vaseline (petroleum jelly) daily for six months.

But they also discovered that Vaseline – the cheapest option – worked as well as the others and was the least costly.

Eczema can be devastating. Beyond the intractable itch, a higher risk of infections and sleep problems, a child with eczema means missed time from school, missed time from work for parents and huge out-of-pocket expenses. So if we can prevent that with a cheap moisturizer, we should be doing it,” says Dr. Steve Xu, a resident physician in dermatology there.

The study appears in JAMA Pediatrics.