In 1846, Ignaz Semmelweis observed that Austrian women whose babies were delivered by hospital-based students and physicians moving between the morgue and the obstetrics ward had higher mortality rates than those whose babies were delivered by midwives. He insisted the students and physicians wash their hands with a chlorine solution between patients.1
As a result, mortality rates dropped, providing the first evidence that cleansing contaminated hands with an antiseptic agent between patient or cadaver-patient contacts reduces transmission of contagious diseases more effectively than handwashing with soap.2
But chlorine, even diluted with water, is not a gentle solution. Its probable that many healthcare workers in the mid-1800s suffered from dry, chapped, and cracked hands; i.e., contact dermatitis, which opened up new avenues for septic flow. Unfortunately, they may not have realized this danger. Scientists now recognize two important facts: damaged skin often harbors increased numbers of pathogens that are more difficult to reduce by washing than they would be from intact skin, and damaged skin sheds more organisms than healthy skin.3
Hand Hygiene Compliance
Although most of todays physicians, nurses, support staff, and even patients, know that proper hand hygiene, defined as any method that removes or destroys microorganisms on hands,4 is the primary method for controlling infections in healthcare institutions,5-6 many simply do not comply with professional hand hygiene guidelines.7 Skin irritation from hand cleansing agents an occupational hazard8-9 constitutes one substantial barrier to hand hygiene adherence.10
In addition to frequent washing, another well-acknowledged culprit in causing contact dermatitis of hands is the use of latex gloves manufactured with powdered cornstarch to improve the ease of donning.
Cornstarch is a known food for bacteria that easily can invade and infect chapped, cracked hands inside the gloves. It also can become airborne, affecting patients and medical practitioners who might inhale it.11 When using gloves as a protective barrier, it is equally important that hands be washed and dried both before donning and after removing them.
Decades of experience have taught that moist, intact skin is the first line of defense against transmitting infection. Therefore, the lack of intact hand skin poses serious health risks, allowing for cross-contamination by transient flora and pathogens in healthcare settings.12 To help healthcare workers maintain skin integrity, they need adequate information about the possible adverse effects of the hand hygiene agents used in their respective institutions.
Skin, Hygiene and Irritants
This information starts with understanding hand skin, the structure of which begins with the outermost skin layer, composed of flattened dead cells (the stratum corneum). These are attached to each other to form a tough, horny layer of keratin mixed with several lipids, which help maintain hydration and pliability, and form the primary protective skin barrier.13 The outermost layer of skin is completely replaced every two weeks when a new layer is formed.14 Healthy skin sheds approximately 107 particles into the air daily, and approximately 10 percent of these contain viable bacteria15 more in males than females with up to a five-fold variation between people using the same hygienic regimen.16
When the skin barrier is compromised by hand-hygiene practices such as scrubbing with harsh disinfectants or soaps, the resultant skin dryness, irritation and cracking offer contagious microbes new opportunities for transmission. Palms, especially, are quite permeable to water.17 A 1998 study showed that nurses with damaged hands were nearly two times as likely to be colonized with S. hominis, S. aureus, gram-negative bacteria, enterococci, and Candida, and had more species colonizing their hands as those with undamaged hands.18 In addition, the antibacterial characteristics of skin often are linked to its normal acidic pH, which can be changed by frequent handwashing.19 Some soaps have been related to long-term changes in skin pH, reduced fatty acids and changes in resident flora such as Propionibacter.20
Ask a healthcare professional about his or her chapped hands and the predictable answer likely will address the active ingredient in handwash formulations purchased by medical institutions. However, two studies one recent, one in 1991 suggest inactive ingredients may significantly affect hand skin integrity. While there has been very little research to examine which agents are most irritating, the 1991 research in Europe provided some of the first insights into the issue.
University Hospital in The Netherlands tested the irritancy of six common handwash antiseptics using repeated open exposures on human skin to determine which antimicrobial would cause the least harm. The antiseptics were 0.5 percent CHG in 70 percent ethanol, 4 percent CHG in water, 70 percent ethanol, 1 percent iodine in 70 percent ethanol, 10 percent povidone-iodine in water, and .25 percent sodium hypochlorite in water.21 Twenty subjects received open exposures of each antiseptic in its normal use concentration for 30 minutes, twice daily for four consecutive days.
Evaluation was performed by visual scoring, subjects irritancy scoring and other non-invasive methods. The antiseptics that were non-irritating were 4 percent CHG in water, CHG 0.5 percent in 70 percent ethanol, 70 percent ethanol, and 10 percent povidone-iodine.22 Of those agents, only the 4 percent and 0.5 percent CHG products are known to provide residual kill for up to six hours after washing. Povidone-iodine, which kills bacteria on contact, is neutralized by blood and other organic materials,23 and, while alcohols kill is immediate, it is common knowledge that once alcohol dries, it no longer is effective. In addition, experience teaches us that alcohol applied on chapped, cracked hands can be quite painful.
Irritants and Handwashes
A 2005 unpublished and more extended skin irritation study confirms the 1991 findings that CHG is the least irritating and most effective antimicrobial skin wash. It also suggests the need to further examine the role played by inactive ingredients in causing hand irritation. For example, a 4 percent generic CHG and other formulations of lower CHG concentrations (1 percent and 2 percent) were shown to cause skin irritation while a branded 4 percent CHG product had virtually no effect on tested hands.24 This clearly indicates that inactive ingredients, not CHG, play a greater role than previously suspected in causing hand contact dermatitis among healthcare workers.
This test, more extensive than the European one, included 12 antiseptics commonly used in healthcare facilities plus a negative control (water) and a positive control (sodium lauryl sulfate). Twenty-five adult subjects submitted to a 14-day cumulative irritation test to the upper arms or upper back. The antiseptics were placed in a patch system using a nonporous plastic, hypoallergenic adhesive tape. Each participant received 14 consecutive daily applications of each of the 12 test articles with the positive and negative controls. The assignment of test articles to each test site (arm or back) was randomized. Subjects removed the patches 30 to 60 minutes before they reported to the lab each day, approximately 24 hours after the patch application, when dermatologists performed visual evaluations.25 Irritation scores ranged from 0 to 7; for example, with gradations between consecutive numbers, 0 was no evidence of irritation; 3 was erythema and papules, and 7 showed strong reaction spreading beyond the test site. Skin effects were scored from slight glazed appearance to a mid-point of glazing with peeling and cracking or glazing with fissures to glistening to small petechial erosions and/or scabs.
The antiseptics fell into three categories: probably mild, possibly mild in normal use, or experimental cumulative irritant. As the accompanying graph shows, the only probably mild antiseptic comparable to the negative water control was the branded 4 percent CHG. The 2 percent and other 4 percent CHG products that were tested were more irritating than the 4 percent branded product, which leads to a logical conclusion that the inactive ingredients in CHG products might be primary contributors to irritation. Among all agents tested, two alcohol and several 2 percent and 4 percent CHG formulations were the most irritating.
Alcohol-based and alcohol foam products fell into the possibly mild and the experimental cumulative potential irritation groups. Again, this suggests that an antiseptics inactive ingredients may have a greater influence on potential irritation than the level of CHG or alcohol. Four of the tested antiseptics 2 percent CHG (B2), one brand of alcohol (Alcohol 2), a generic 4 percent CHG (D) and the alcohol wash were more irritating than the positive control - sodium lauryl sulfate. Another alcohol product, a foam, as well as 1 percent CHG and three other generic 4 percent CHGs (A, B, and C) were ranked possibly mild vs. probably mild the most benign category. The branded 4 percent CHG was the only tested antiseptic that was rated probably mild.26
While alcohol gels with emollients require about one-fourth as much time to use as washing at a sink and they kill many bacteria, viruses and some fungi on contact, they have no residual kill function. Furthermore, alcohol gels are known not to remove spores, prions, feces, or other soil that may remain on the hands; rather, they merely rub the remaining dirt around the hands. When alcohol gels or creams are used, to be effective, they should be applied only to completely dry and clean hands rather than immediately following a handwash. This is because the water remaining in pores and micro-cracks in the skin following a handwash, is believed to dilute the alcohol and reduce its antiseptic effectiveness.27 In addition, personal observations indicate the same emollients that make the alcoholbased antiseptics gentle on the hands may build up during the work day, leaving a greasy or sticky residue.
According to the CDC, it is important to note that the use of alcoholbased hand antiseptics does not replace the need for frequent and proper hand washing. In addition, many alcohol-based hand antiseptics have very poor activity against bacterial spores, protozoan cysts and certain nonenveloped viruses such as noroviruses. They have very good to excellent activity against many bacteria and some enveloped viruses. In general, ethanol-based hand antiseptics appear to have greater antimicrobial activity against viruses than isopropanol-based products, although both appear to offer some activity against these pathogens.28
One solution might be to encourage time-challenged healthcare professionals to employ a dual hand-hygiene strategy. That is, in the best of healthcare practices, they would use a non-irritating branded 4 percent CHG with six-hour residual kill as a first, middle, and last wash of the day. Between the branded 4 percent CHG washes, they would use an emollient-enriched alcohol gel or foam on entering and leaving every patient room.
Today, unlike the days of Semmelweiss and other infection control pioneers, armamentariums of antiseptics exist. While choice is good, the features, strengths and weaknesses of each active and, especially, inactive ingredients must be understood by those selecting antiseptics. If an antiseptic wash kills bacteria on the hands, but eventually leaves the skin dry, cracked and bleeding, the antiseptic could be doing more harm than good.Â
Milt Hinsch is technical services director of Molnlycke Health Care US.
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