Background
One of the scariest moments in the life of an anaesthetist is a sudden catastrophic anaphylactic reaction. Nowadays, anaesthetists are well-trained in recognising and managing this life-threatening complication, and we face such a scenario at least half a dozen times in our professional lifetimes. Often, the triggering agent is a muscle relaxant, such as rocuronium. Whilst we know that this drug can rarely be a potential problem, some surgeries require a complete relaxation of the muscles. Due to its fast onset and reversibility, rocuronium is one of the most commonly used muscle relaxants worldwide.
A true allergic reaction requires that the patient has been exposed to a medication before. The second time around, the body recognises the medication as a foreign substance and unleashes the full power of the immune system against the intruder. In reality, we find many patients who have previously never had an anaesthetic and respond with a full-blown anaphylaxis to rocuronium or similar medications. How could that possibly be?
The fact that anaphylaxis to rocuronium occurs more commonly in women might be a little giveaway here. Our bodies are exposed to thousands of chemicals we voluntarily put onto our skin. From beauty products to washing powders, from cleaning solutions to air fresheners, there has been an explosion of chemicals in our environment. And inevitably, we are paying the price for this unexpected assault on our bodies.
Silent Intruders
An alarming new study reveals that a pervasive form of human pollution is infiltrating our bodies in unexpected ways. Researchers from the University of Birmingham have discovered, through human tissue models, that ‘forever chemicals’ such as PFAS (per- and polyfluorinated alkyl substances) can surprisingly penetrate our skin.
When these resilient substances were first developed over fifty years ago, companies like DuPont—the manufacturer of Teflon—knew that some of these non-stick, waterproof materials were “highly toxic” if inhaled and “moderately toxic” if ingested.
As early as 1961, confidential company documents indicated that Teflon’s lead toxicologist advised against certain PFAS types contacting the skin.
Now, in 2024, independent scientists have shown that skin exposure is a significant pathway for some of the most common and extensively studied PFAS chemicals.
Today, PFAS are prevalent in various skincare products, including sunscreen, moisturizers, and cleansers.
“The notion that these chemicals couldn’t be absorbed through skin due to their ionized nature was a misconception,” explains environmental scientist Oddný Ragnarsdóttir. “Their electrical charge, which helps repel water and stains, was thought to prevent them from crossing the skin membrane.”
However, experiments by Ragnarsdóttir and her team indicate that this is not always the case.
Currently, over 12,000 known PFAS variants are on the market. However, scientists still lack comprehensive knowledge about the connection between cosmetic products and the presence of these chemicals in the bloodstream, their potential toxic effects, and the harmful levels of exposure.
Researchers examined 17 of the most common and well-researched PFAS to address this. Each chemical was applied to a 3D human skin model, which simulates real human skin, to observe absorption rates.
Of the PFAS tested, 15 permeated the skin model within 36 hours. One particularly concerning chemical, PFOA (perfluorooctanoic acid), known for its toxicity, was phased out in the US in the early 2000s but continues to contaminate the environment and is often found in tap water.
In 2023, PFOA was globally banned under the UN Stockholm Convention due to its carcinogenic effects when ingested or inhaled. The study now indicates that PFOA can also be absorbed through the skin.
Of the PFOA applied in the study, approximately 13.5 per cent entered the bloodstream, and 38 per cent remained in the skin, potentially entering the bloodstream later.
A recent study involving a single male volunteer confirmed that if PFOA is present in sunscreen, it can indeed be absorbed through the skin into the bloodstream.
“It is very likely that a part of the absorbed PFOA is distributed from blood to other fluids and tissues,” the study authors suggest. “However, there are very few reports on PFAS levels in human organs and blood.”
Today, PFOA has been replaced by shorter-chain PFAS, but the recent research suggests that shorter chains are absorbed more easily. For instance, perfluoropentanoic acid (PFPeA), a shorter-chain chemical, was absorbed into the skin at four times the rate of PFOA.
PFPeA, commonly used in food packaging, has shown systemic toxicity in mouse models when applied to the skin, though testing these chemicals directly on humans poses ethical challenges.
A 3D skin model offers a valuable method to study these effects without endangering humans.
Earlier this year, this technique demonstrated that other persistent chemicals, such as polybrominated diphenyl ethers (PBDEs) used in flame retardants, can also penetrate the skin and enter the bloodstream within a day.
Many questions about ‘forever chemicals’ and their skin absorption remain unanswered, but when toxicologists themselves start avoiding certain cosmetic brands due to PFAS exposure concerns, it’s time to take notice.
Bottom Line
In the past, the field of toxicology examined the impact of increasing doses of one single substance. Nowadays, however, we face thousands of substances in small amounts entering our bodies through breathing, food and our skin. We have very little understanding of the long-term impacts of these chemical cocktails. Still, the field of functional medicine increasingly empowers us to recognise and mitigate those impacts through education and careful application of nutraceuticals to improve detoxification processes within our bodies.
