Thirdhand smoke can trigger skin diseases, study warns

Smoke dust may lead to initiation of inflammation-induced skin diseases like contact dermatitis and psoriasis, scientists say

The residual pollutants from tobacco smoke that remain on surfaces, also known as thirdhand smoke, may trigger skin diseases, according to a new study.

These dust particles, known as THS, that remain after tobacco has been smoked, can remain on indoor surfaces indefinitely and lead to potentially harmful exposure to both smokers and non-smokers, says the research, published recently in the journal eBioMedicine.

Researchers from the University of California, Riverside, found that acute exposure of the skin to THS elevates levels of molecules in the body that are linked to the initiation of skin diseases like contact dermatitis and psoriasis.

“We found exposure of human skin to THS initiates mechanisms of inflammatory skin disease, and elevates urinary biomarkers of oxidative harm, which could lead to other diseases, such as cancer, heart disease, and atherosclerosis,” study co-author Shane Sakamaki-Ching said in a statement.

In the study, scientists assessed 10 healthy non-smoker participants of 22 to 45 years age, who each wore clothing impregnated with THS.

The participants did not know their clothing had THS and either walked or ran on a treadmill for at least 15 minutes each hour to induce perspiration and increase uptake of THS through the skin.

Scientists then took blood and urine samples from the participants at regular intervals to identify protein changes induced by the THS.

Researchers compared the results with those from control exposure participants who wore clean clothing.

“We found acute THS exposure caused elevation of urinary biomarkers of oxidative damage to DNA, lipids, and proteins, and these biomarkers remained high after the exposure stopped,” said Dr Sakamaki-Ching said.

“Cigarette smokers show the same elevation in these biomarkers. Our findings can help physicians in diagnosing patients exposed to THS and help develop regulatory policies dealing with remediation of indoor environments contaminated with THS,” he added.

While the smoke particle exposure in the 10 participants were “relatively brief” and did not cause significant changes in their skin, scientists say the molecule changes in their blood, associated with early-stage activation of contact dermatitis, psoriasis, and other skin conditions, were elevated.

“There is a general lack of knowledge of human health responses to THS exposure,” Prue Talbot, another author on the study, said.

“If you buy a used car previously owned by a smoker, you are putting yourself at some health risk. If you go to a casino that allows smoking, you are exposing your skin to THS. The same applies to staying in a hotel room that was previously occupied by a smoker,” Dr Talbot added.

Scientists say the findings underscore the idea that skin exposure to THS could lead to initiation of inflammation-induced skin diseases.