Fotinos S. Panagakos, DMD, PhD
Director of Environmental Safety, UMDNJ-New Jersey Dental School
Teri E. Lassiter, BS
Among Dr. William Halsted's many contributions to surgery was the introduction of rubber gloves. In 1889 and 1890, his operating room nurse developed dermatitis on her hands and arms from a solution of mercuric chloride. Halsted had the Goodyear Rubber Company make two pairs of experimental gloves for her, and they proved so satisfactory that eventually his entire surgical team began using them.
Nearly a hundred years later, gloves became a necessity, as concern rose about blood-borne disease transmission - particularly AIDS.
With the adoption of "universal precautions" by the Centers for Disease Control (CDC) in 1987 and institution of the Bloodborne Pathogens Standard by the Occupational Safety and Health Administration(OSHA) in 1992, use of latex rubber gloves by health care professionals increased markedly. So, too, have accounts of latex allergies.
Between October 1988 and April 1992, more than 1,100 instances were reported to the Food and Drug Administration (FDA), including 15 patient deaths associated with mucous membrane contact with barium enema tips. This caused the FDA to request that physicians report patients who demonstrated allergic reactions to latex.
A 1992 study on latex allergies in health care workers suggested that approximately 6.5 percent of those exposed to latex had become sensitized. Later data, however, found the prevalence of allergy and sensitization in the 3 to 6 percent range, compared to 1 percent for the general population. These statistics place health care workers in a high risk group for susceptibility to latex allergy and increase concern about the problem.
Across the country approximately 6 percent of surgical physicians, as well as an estimated 8 to 9 percent of nurses, have been affected.
The increase in use of latex gloves - from 1.4 billion pairs in 1986 to 8 billion in 1993 - correlates directly with implementation of OSHA and CDC guidelines. OSHA estimates that 5.5 to 6.4 million health care workers in the U.S. wear the gloves routinely and that between 250,000 and 500,000 experience some degree of allergy to latex protein.
One explanation for the rise in allergies is that increased use leads to greater protein sensitization of those predisposed to other allergies, and another has to do with supply and demand. This theory maintains that manufacturers produced large quantities of substandard gloves between 1986 and 1987, when demand was great and supply was short.
New companies had an easy time entering the market and did not follow necessary procedures for removing residual chemicals and excess latex proteins in the post-processing washes. In their rush to get the product to market, the latex was not aged properly either. It is during the aging, of approximately a week, that many protein levels are reduced.
In 1992, the FDA established regulations governing glove manufacturing, saying it was an "effort to minimize the possibility that latex contaminants are either a source or a contributing factor in the adverse reactions attributed to various types of latex devices."
Natural rubber latex can produce three distinct types of reactions: irritant contact dermatitis, allergic contact dermatitis and urticaria. Irritant contact dermatitis results in damage or injury to skin. It usually occurs when gloves have been worn for long periods preventing exposure to air. Skin cells swell with fluid, become weakened and more susceptible to injury.
Hand washing exacerbates the condition because people tend not to dry their hands completely, thus allowing the glove powder to bind with the skin. This problem is not related to an immune response, and it is easily resolved by using nonpowdered latex gloves or cotton liners and by making sure the hands are thoroughly dry before putting gloves on.
Allergic contact dermatitis is a Type IV/cell-mediated allergic response to specific components of the latex product. It develops over time - as more cells become sensitized, both the area and severity of the allergic reaction increase. Symptoms generally occur from 48 to 72 hours after exposure. The main allergens are the accelerates used to shorten the manufacturing process. Reports of sensitivity to them was first reported in 1979. Antioxidants, vulcanizers, organic pigments, and possibly glove powder, which contains epichlorohydrin and sorbic acid, are most likely to blame.
This type of dermatitis is usually confined to the areas that have been in direct contact with the latex product - the hands among health care workers. A study of delayed allergic reactions related to rubber products found gloves to be the cause of eczema in 58.3 percent of all cases. Glove exposure will often produce lesions on the surfaces of the hands, wrists and distal portion of the forearms. Acute symptoms of extreme itching, erythema and blisters are common. As lesions heal, cracking, crusting and peeling skin may occur on the affected areas.
Certain chemicals, such as methyl methacrylates which are used in dentistry and orthopedics, can penetrate the gloves. These should be considered a cause of dermatitis if evaluation does not reveal allergy to rubber chemical or latex.
The third type of reaction is urticaria. This is a Type I/IgE medi- ated allergy, and it is felt that it stems directly from the "natural proteinaceous" products produced by the rubber tree, Hevea brasiliensis. Reactions can range from mild and localized to generalized anaphylaxis. Symptoms can appear within minutes or take up to an hour before they manifest.
Localization of symptoms is dependent upon the route of exposure, the degree of allergic sensitivity, and the differences between the allergic potential of different organs. Skin that has been in contact with the latex product is usually the first to be affected, and sometimes nasal, ocular and pulmonary symptoms follow. The gastrointestinal and cardiovascular systems are less often affected. Contact urticaria was the first reported manifestation of immediate latex allergy.
Type I reaction to latex can cause more severe symptoms in patients and health care workers with frequent exposures to latex products. Localized symptoms may include itching, urticaria, or mild erythema with a burning or itching sensation. Generalized symptoms might include edema, asthma, dizziness, rhinitis, conjunctivitis and life-threatening anaphylactic reactions. Any of these symptoms may appear more rapidly with occupational exposure if the hands are wet, allowing latex proteins to react quickly with the skin, or if the gloves are too tight and exert unnecessary pressure.
There are several alternatives to latex products. Hypoallergenic gloves - latex with fewer of the proteins - are designed to minimize, not eliminate the likelihood of allergic response. Vinyl gloves offer a synthetic alternative and contain no protein allergens. However, their ability to prevent transmission of some blood-borne diseases has been questioned. They tend to be less flexible than latex and have reduced elasticity. Because of bacterial penetration, they are suitable for short-term, non-surgical procedures, like physical examinations and radiology procedures.
Neoprene gloves, made from polychloroprene, can contain small amounts of natural rubber latex. They are resistant to chlorinated solvents and alcohol, and their elasticity provides a sure fit. Nitrile gloves, most commonly used for handling instruments during cleaning, are now available in an examination glove form. They are produced from a synthetic product and contain no natural rubber proteins. Studies have shown that they resist cuts and punctures, as well as have stronger resistance to solvents than latex and neoprene gloves.
The American Academy of Allergy and Immunology has issued a protocol recommending who should be tested for latex allergy. Those considered to be at high risk are health care and latex industry workers, children with spina bifida, as well as people with positive risk factors. They include: previous allergic reaction to latex or products containing latex; previous unexplained anaphylaxis; hand eczema; allergic reaction, such as oral itching from cross-reactive foods; and multiple surgeries in childhood. Diagnosis of latex allergies requires careful medical histories, physical examinations and allergy tests.
The radioallergosorbent test (RAST) is most commonly used. It is capable of measuring minute quantities of IgE in the blood - in this case IgE that is latex specific - to determine allergic reaction.
The skin prick test, which is commonly used to determine allergies, will immediately produce a wheal and flare reaction in a patient who is latex sensitive. The drawback is that an allergic patient could develop anaphylaxis. The latex antigen can also be injected intradermally, but this test may also produce anaphylaxis and the antigen cannot be wiped away.
A common test for sensitivity is to ask a patient to insert one finger in a latex glove. If no itching or urticaria occurs within 30 minutes, the test is repeated with the whole glove over a premoistened hand and a synthetic control glove on the other hand. Reaction usually occurs within 30 minutes. However, it is not always possible to differentiate between an irritation and an allergic response.
Natural rubber latex can be found in more than 40,000 consumer products, ranging from balloons to diapers to elastic used in clothing.
A thorough medical history is important as a first step in identifying possible allergies to protein latex. The majority of people who develop this hypersensitivity have either a history of previous allergic conditions, such as hay fever, or have become sensitized over time from exposure to natural latex products.
Recent research has linked an intolerance to certain foods - most commonly bananas, chestnuts and avocados - to latex intolerance. In dental patients, hypersensitivity produces reactions to gloves, dental dams, blood pressure cuffs, orthodontic elastics and anesthetic gas masks.
The FDA proposed a rule regarding the labeling of devices containing latex in June 1996, but it has yet to be finalized. The agency has published recommendations for health care workers to deal with the problem, and has asked them to report incidents of latex sensitivity to the FDA Problem Reporting Program at 800-638-6725. Maryland residents should call collect: 301-881-0256.
This article was adapted from "Latex Allergies: How they affect the dental profession," which appeared in the spring 1997 issue of the Journal of the New Jersey Dental Association.
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