(Reuters Health) - Many moisturizers promoted as remedies for skin problems like eczema and labeled as `fragrance-free’ or `hypoallergenic’ may still contain chemicals that can cause irritation, a recent U.S. study suggests.

Researchers asked Amazon, Target and Walmart to name their top 100 best-selling whole-body moisturizers sold online. Then the researchers assessed how well these popular products moisturized the skin, whether or not their ingredients might trigger allergic reactions and how much they cost.

Only 21, or 12 percent, of the 174 individual products tested were free of allergens, the study found.

Many of the moisturizers contained fragrances and chemicals known as parabens and tocopherol, all of which can cause rashes and worsen skin conditions like eczema and psoriasis.

This means patients can’t assume that moisturizers marketed as hypoallergenic, fragrance-free or even dermatologist-recommended will actually help skin conditions, said lead study author Dr. Steve Xu of Northwestern University Feinberg School of Medicine.

“Ultimately, there is no such thing as a zero-risk cosmetic product,” Xu said by email.

“For moisturizers, white petroleum or pure shea butter are lower risk, but trusting the labels is not enough,” Xu added. “Making sure there are as few ingredients as possible is also a good thing to double check.”

Moisturizers are a great solution for patients with skin disorders because they retain moisture in the skin, reduce inflammation, help prevent infection, are widely available and can be more affordable than prescription skin remedies.

But the study found products marketed to appeal to people with skin problems like eczema and psoriasis tended to cost more, even though they didn’t necessarily avoid ingredients that could make these conditions worse.

Half of the products labeled “dermatologist recommended” cost at least 79 cents an ounce, while moisturizers without that description were typically 59 cents an ounce, researchers report in JAMA Dermatology.

When moisturizers claimed to be “phthalate free,” they tended to cost about $1.38 an ounce, compared to 59 cents an ounce without that distinction.

At the same time, there wasn’t a statistically meaningful difference in pricing based on whether or not the moisturizers were free of known allergens identified by the North American Contact Dermatitis Group (NACDG), which determines if a product contains typical skin allergens such as fragrance mix, parabens or tocopherol.

The top three most affordable moisturizers in the study that were free of NACDG ingredients were Ivory raw unrefined shea butter, Vaseline original petroleum jelly and Smellgood African shea butter.

The most popular moisturizers, according to the study, were lotions (59 percent), followed by creams (13 percent), oils (12 percent), butters (8 percent) and ointments (2 percent).

Roughly 83 percent of moisturizers labeled “hypoallergenic” contained at least one ingredient believed to potentially cause allergic reactions, the study found.

And 45 percent of products claiming to be “fragrance free” actually contained a fragrance or a botanical ingredient.

The study wasn’t a controlled experiment designed to prove whether or how specific ingredients might exacerbate or relieve skin conditions.

Prices found online when researchers did the study also might not reflect current or typical costs for moisturizers, the authors note.

For people with sensitive skin or problems like eczema or psoriasis, however, the study confirms that reading labels may not necessarily guarantee a safe or effective product, said Dr. Matthew Zirwas, author of an accompanying editorial and member of NACDG.

“We know that the only definite harm to consumers from personal care products is allergic reactions to ingredients such as fragrances, preservatives, etc.,” Zirwas said by email. “This study confirms for us that consumers can’t tell which products don’t have this risk by looking for terms like hypoallergenic or fragrance free.”

SOURCE: bit.ly/2xYfXwd JAMA Dermatology, online September 6, 2017.