Bravo to all the medical care institutions that are finally taking hand washing seriously! This is vitally important for patient safety and is likely to reduce bad outcomes and overall costs to the medical care system.
However, there are still choices that need to be made sensibly as we implement these practices. We must remember not only that waterless hand cleaners do not remove body substances such as blood, saliva, urine, and feces, but also that they do not kill or remove the spore forms of bacteria that can cause Clostridium difficile infections. Hand washing with real soap and running water for 15 seconds still has an important role. Paper towel dispensers should not require the user to crank a handle or push a lever to dispense towels. By touching those handles and levers that cannot be considered clean, we recontaminate our just-washed hands the same way we would if we turned off the faucet by handling the water controls.
Now consider the composition of the waterless hand cleaners. The active ingredient in many of them is ethyl alcohol (62%). This is the same alcoholic substance found in alcoholic beverages, so most of us are fairly confident that if we absorb a little of it, and it can be absorbed through the skin,(1) it is unlikely to be harmful. An alternative product in this class contains the active ingredient isopropyl alcohol in similar proportion. That alcohol is the one we are familiar with as rubbing alcohol and also is the one found in the alcohol swabs commonly used for cleaning the skin for phlebotomy, intravenous catheters, and injections. It too can be absorbed through the skin.(2) Blood levels of 0.5 to 1.8 mg/L were recorded in 10 adult subjects who applied isopropyl alcohol gel hand cleaners every 10 minutes for only 4 hours.3 In the past, isopropyl alcohol was used for “alcohol baths” to reduce fevers in children and adults. That procedure was stopped because it was found to be toxic, causing confusion and delirium, stupor, coma, myocardial depression with hypotension, gastrointestinal bleeding, and neuropathy.(4, 5, 6) There are few data on what might be the long-term results of repeated daily exposure.(7)
Another substance found in some of the waterless hand cleaner formulations is parabens. The role of parabens in skin lotions, cosmetics, and drugs is as a preservative. It is well absorbed from the skin and excreted in the urine.(8) Recent studies have demonstrated that parabens may have some estrogenic actions in various animal models, raising the question of its safety, especially for women who have been treated for estrogen-receptor positive breast cancer.(9, 10) Many such women take drugs (aromatase inhibitors) to prevent their bodies from making estrogenic substances, and these aromatase inhibitors have been shown to decrease the rates of breast cancer recurrence.(11) Some premenopausal women at high risk of developing breast cancer undergo oophorectomy or take anti-estrogen drugs to decrease their risk of developing breast cancer.(12) One recent study demonstrated measurable levels of parabens in excised breast tissue samples.(13) Although there are limited data, and some have argued that the estrogenic potency of parabens is too low to have a significant effect at the likely exposures from cosmetics, drugs, and skin creams, it seems prudent to avoid unnecessary exposure to possibly harmful substances. In the case of waterless hand cleaners, regular use will probably result in dramatically larger volume exposures than the use of most cosmetics. It is not hard to imagine 50 to 100 uses per shift for a nurse in active patient care.
Adverse effects of parabens might not be limited to women. Oishi(14) demonstrated decreased testosterone levels and sperm production in an animal model exposed to parabens.
Another issue that should be considered is that some substances can increase skin absorption of other substances. This phenomenon is called absorption enhancement or permeation enhancement and is of interest to those developing methods for delivering drugs through topical applications.(15) Alcohols have been demonstrated to act as permeation enhancers. So, if one adds parabens to an alcohol-based hand cleaner, absorption of the parabens might be significantly increased. At least 1 study in the literature shows just this effect in a laboratory model of guinea pig skin, with ethanol increasing parabens absorption through the skin.(16)
We live in a country where regulation of the use of chemicals is limited, especially for substances that have been in common use for many years and were therefore grandfathered under the Toxic Substances Control Act, passed by Congress in 1976. There is debate about whether the current statute gives the Environmental Protection Agency (EPA) sufficient authority to regulate commercial use of chemicals, based on principles of protecting health and the environment.
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— Marcia R. Silver, MD, FACP
This article was originally published in the October 2008 issue of The American Journal of Medicine.
