Going powder-free is first step to beat latex allergies
Powderless gloves limit aerosolization of proteins
Reacting to growing concerns about latex allergies among health care workers and patients, many hospitals have curtailed the use of latex gloves used for examinations and surgery. But making the transition begs the question of how far to go and what amount of latex glove use is safe.
Despite noteworthy advances in synthetic alternatives, surgeons and other health care workers still consider latex gloves the gold standard because they embody a unique combination of strength, flexibility, durability, and tactility. Totally eliminating latex from the glove equation, particularly in the operating room, may be an unrealistic goal for most institutions.
But at the very least, health care facilities should eliminate the use of powdered latex exam and surgical gloves, according to Robert G. Hamilton, PhD, associate professor of medicine and pathology at the Johns Hopkins University School of Medicine in Baltimore.
"Powdered latex gloves represent the group of products that historically have contained the highest levels of allergens. By eliminating them, you eliminate the cornstarch that carries the protein allergen into the air, and thus you reduce contact exposure," Hamilton says.
Airborne allergens pose greatest threat
A Mayo Clinic study demonstrated that airborne latex allergen concentrations varied from 10 to 208 ng/m3 in areas where powdered latex gloves were used, compared with 0.3 to 1.8 ng/m3 where powdered latex was never or seldom used.1
"Problems [related to latex glove powder] don’t usually occur in the OR suite, but in the pre- and postoperative bays where you have a lot of glove changes and a lot of accumulation of latex glove powder," says Lauren Charous, MD, director of the allergic and respiratory care center at the Milwaukee Medical Clinic and chairman of the American College of Allergy, Asthma and Immunology Latex Hypersensitivity Com mittee in Arlington Heights, IL.
"In most situations, you can use powderless latex gloves for both surgery and for exams," says Charous. "Getting rid of powdered latex gloves is a reasonable, doable goal, and except under special circumstances, you don’t need a separate non-latex OR suite if you use only unpowdered latex gloves because they don’t produce the aerosolized proteins."
Powderless gloves not only minimize aerosol ization of latex proteins; they typically contain far lower amounts of the offending allergens that cause IgE/histamine-mediated (Type I) reactions, because they undergo more thorough washing and chlorination during manufacturing. Wava Truscott, PhD, vice president of scientific affairs for the Safeskin Corp. in San Diego, notes that powdered latex gloves can contain 3,000 times more allergen than unpowdered gloves.
Kenneth K. Meyer, MD, FACS, adjunct scientist at the Guthrie Foundation for Medical Research in Sayer, PA, has found that allergen levels in powdered latex gloves can be as high as 1,039 [gm]g/g, whereas the content of powder-free latex gloves rarely exceeds 293 [gm]g/g, as measured by the Lowry test.
These variations are significant, says Meyer, who says nearly 70% of patients with documented latex allergy test positive in the presence of powdered latex gloves containing more than 50 [gm]g/g of latex allergens. But in the presence of gloves containing minimal amounts of latex allergens, only 11% of latex-allergic subjects tested positive.
While the Lowry test is considered the national standard for determining latex protein content, it has been criticized because it lacks sensitivity and specificity. Meyer and others ascribe a great deal more credence to immunochemical assays, such as the LEAP assay and the RAST assay.
Glove users, Meyer adds, should never assume that gloves are protein-free based on laboratory tests, powdered or not. In a report published in the Bulletin of the American College of Surgeons, Meyer writes: "Laboratory tests cannot determine that no protein is present in the glove, and no manufacturer can honestly claim their latex gloves to be protein-free just because protein is undetectable by tests. Clearly, gloves with undetectable protein by the immunological methods have a significantly less likelihood of causing reaction than those tested by the Lowry method."2 He adds that powder-free gloves, because they hydrate more slowly than their powdered counterparts, "maintain their tensile and tactile properties as well as their resistance to chemical and viral transfer."
Meyer stresses that if latex gloves are present in the OR, only powder-free models be worn. To the degree possible, surgeons should know the protein content of the gloves they wear. Meyer advises glove users to obtain from manufacturers the results of immunochemical tests (LEAP and RAST assays), not Lowry test results. According to Meyer, surgeons should insist that their latex gloves contain less than 10 [gm]g/g as measured by LEAP assay or less than 100 allergen units/ml as measured by RAST. The "ideal" latex glove contains less than 1 [gm]g/g as measured by LEAP and 1 to 14 allergen units/ml by RAST.
Policies not enough
Despite all the sensible advice regarding latex, a study conducted by researchers at the University of Connecticut Health Center in Farmington demonstrates that simply implementing a policy to reduce powdered-latex glove use is ineffective unless coupled with a concerted and ongoing education program. Marcia Trapé, MD, medical director of the hospital’s Employee Health Service, stated that "restricting the use of powdered latex gloves is but a first step in solving the problem of latex sensitivity among health care workers." (See Hospital Employee Health, May 1999, pp. 55-57.)
The University of Connecticut had implemented a policy recommending the use of nonlatex or powder-free latex exam gloves for nonsterile procedures. But one year later, half of nearly 1,100 employees surveyed said they still wore latex gloves, and 16% still used powdered latex gloves. Among workers who reported skin reactions to latex, 84% were still wearing it, even though they had access to nonlatex alternatives. In addition, health care workers who experienced a higher incidence of latex allergy symptoms wore powdered latex gloves more frequently than their colleagues who suffered fewer allergic episodes.
The survey data also showed that employees in high-exposure categories (which included surgical medical staff, non-surgical medical staff, and nursing staff) were 12 times more likely to develop latex-related skin symptoms than those considered at lower risk, such as maintenance workers and patient transporters.
The dangers of latex exposure were widely publicized by a NIOSH safety alert issued in 1997 (see HEH, September 1997, pp. 97-101), which stated that "If you choose to use latex [gloves], use powder-free low protein."
Earlier this year, the Occupational Safety and Health Administration (OSHA) issued a technical bulletin recommending that hospitals use powder-free, low-protein latex gloves and provide nonlatex alternatives for health care workers and patients who are allergic to natural rubber latex (see HEH, June 1999, pp. 61-63). OSHA has insisted that the bulletin is simply a strongly worded advisory — not a new regulation — but the document aroused controversy in the medical glove industry, which called the conclusions alarmist.
Undeniably, latex allergy is an issue to be taken seriously, yet the problem’s true scope remains unknown. Estimates place the incidence of latex sensitivity among health care workers at between 8% and 17%. Many become sensitized to latex proteins after repeated exposure (including inhalation) to airborne glove powder, according to experts.
In comparison to other allergies, the incidence of latex allergy is relatively low and it is rarely life-threatening. According to one British researcher, not a single latex-allergy case of fatal anaphylactic shock has been documented anywhere in the world, despite an estimated annual consumption of more than 15 billion latex gloves. But the statistically small risk is little consolation to those whose careers have been severely restricted or even ended by latex sensitivities.
As one latex expert stated, "Although the threat to life from latex products may be extremely small, the allergy symptoms need to be avoided as far as possible. It is therefore in the interest of everyone, including latex product manufacturers, that gloves made of alternative materials are available and that they are used when necessary."3
References
1. Swanson MC, Bubak ME, Hunt LW, et al. Quantification of occupational latex aeroallergens in a medical center. J Allergy Clin Immunol 1994; 94:445-451.
2. Latex allergy: How safe are your gloves? Bull Am Coll Surg 1997; 82.
3. Morris MD. Latex Protein Allergy, the Latest Position. Con ference Paper. Paris: International Latex Conference; 1995.