Why is the burn harmful?

Why steam burns are so dangerous

It is difficult to burn yourself with steam, even if the wound often looks harmless on the surface. Employees at the Swiss research institute Empa have shown for the first time how water vapor achieves its "perfidious effect". According to the results, the top layer of skin cannot fulfill its protective function in the event of burns with steam.

This can happen, for example, when straining pasta. Steam burns are treacherous. Because the burn may look harmless on the surface if the skin is only briefly exposed to the steam. Nevertheless, the lower skin layer can be severely damaged. Why this is so has been unclear until now.

Researchers from Empa's "Biometric Membranes and Textiles" department have solved this puzzle. "We were able to show that the top layer of skin, the epidermis, cannot properly perform its protective function against water vapor," says Rene Rossi, head of the research group.

Directly on the dermis

The steam penetrates through the skin pores to the lower layer of the skin, called the dermis or dermis. "Only there does the steam condense, thereby releasing its thermal energy directly onto the sensitive dermis - and directly triggering second-degree burns," says Rossi.

The scientists examined their thesis on pig skin. The researchers exposed this to hot water vapor or dry heat and then analyzed the water content of the various skin layers using Raman spectroscopy. This is a method that allows statements to be made about material properties through the scattering of light.

The experiments showed that the heat penetrated faster and deeper into the underlying skin layers when exposed to water vapor than is the case with dry heat. The water content of all skin layers increases in the first 15 seconds.

Water vapor slips through

This is because the top layer of skin has pores that are usually much larger than a water molecule. So the water vapor can slip through them unhindered. Only when the epidermis is swollen by the amount of water absorbed do the pores become too small for the water vapor. Then the damage in the lower layer is already done, as the researchers reported in the journal "Scientific Reports".

A problem with all burns is the so-called afterburn effect. The skin releases the heat it has absorbed relatively slowly. This means that the heat can act on the tissue longer and damage it.

In the case of burns with steam, the effect is often particularly strong because the heat can penetrate deeply so quickly. "In the case of a steam burn, the skin must therefore be cooled for a long time and continuously," said Rossi. Two minutes in the ice bath are not enough to dissipate the high amount of energy. (APA, May 10, 2018)