Understanding Latex Allergy
in the Healthcare Setting

WHAT IS NATURAL RUBBER LATEX (NRL)? Natural rubber latex (NRL), commonly referred to as “latex,” is a natural milky substance harvested from the Hevea brasiliensis tree that grows in the tropical climate of Southeast Asia. It is used in the manufacture of many household, industrial, and medical products, including surgical and examination gloves. Latex is primarily composed of rubber, water, and low levels of different types of proteins (compounds that occur naturally in all plants and animals). In technical terms, the generic word “latex” may be used to refer to natural rubber latex or synthetic latex. There are a variety of synthetic latex formulations such as nitrile and neoprene. These materials do not contain natural rubber latex proteins, but may contain chemicals used in their manufacture and processing that are also used in the manufacture of natural rubber latex. Throughout this study guide, natural rubber latex, or NRL, will be used to designate products made from Hevea brasiliensis sap. THE ORIGIN AND EVOLUTION OF NATURAL RUBBER LATEX MEDICAL GLOVES One of the pioneers in the study of surgical infections was Dr. William S. Halstead at John Hopkins Hospital. Because of the dermatitis produced by the mercuric chloride solutions used to disinfect hands and instruments in the surgical suite, Dr. Halstead was in danger of losing one of his operating room nurses. He therefore requested two pairs of rubber gloves with gauntlets for his nurse and assistant from the Goodyear Rubber Company in 1889. The gloves protected the assistants from the harsh disinfecting agents, and in addition, it soon became apparent that they reduced the transmission of infection. Thus, by the early 1900’s the use of rubber gloves was common in the surgical suite in both Europe and the United States. Although the use of latex gloves in surgery became routine after World War I, gloves were not consistently used in other areas of patient care until the onset of the AIDS epidemic and the spread of hepatitis. The Centers for Disease Control (CDC) instituted Universal Precautions in 1987, followed by the Occupational Safety and Health Administration’s (OSHA’s) Bloodborne Pathogen Standards Mandate in 1992, requiring the use of medical gloves upon contact with blood or bodily fluid. This changed healthcare, and glove usage soared. With the increased use of gloves by healthcare workers, there appeared to be an increase in reported reactions to the latex gloves. Reports initially limited to skin irritation and delayed allergic reactions were received; however, the incidence of Immediate (Type I) allergic reactions began to be reported to the U.S. Food and Drug Administration (FDA). These are of much greater concern because of their potentially serious outcome. Many theories have been proposed to explain the sudden increase in the number of persons affected by latex allergy starting in the 1980’s. Even in retrospect, this key question has been difficult to answer because many essential bits of information are missing. One important factor related to the increasing recognition of latex allergy was the discovery that it existed. Once a new disease has been identified and criteria for diagnosis have been formulated, it is much easier for others to recognize similar cases; this is a phenomenon termed “a bias of ascertainment.” Also important was the dissemination of information about latex allergy to healthcare workers and the general public through a variety of media sources. This information allowed many affected persons to recognize their problem and seek diagnosis. With the increased use of latex gloves, it is likely that increased sensitization to latex, the prevalence of symptoms, and recognition happened simultaneously. Also, with the considerable increase in demand for both sterile and non-sterile gloves, there may have been changes in glove manufacturing methods by some manufacturers. Seemingly minor changes, such as shorter wash times and shorter shelf times, produced gloves with high protein content. There was also the proliferation of many new companies with less manufacturing skill that began making gloves, and the quality of those gloves was suspect. According to experts, retention of more proteins, or antigens, than usual in the finished product may have resulted, causing an increase in reactions. Adverse skin reactions from the use of natural rubber latex gloves have been classified into three distinct diagnostic categories: Irritant Contact Dermatitis; Delayed Type IV, or Allergic Contact Dermatitis; and Immediate Type I, or Latex Allergy. IRRITANT CONTACT DERMATITIS Irritant Contact Dermatitis is a non-immune reaction. It is a local reaction from damage to the skin from such things such as detergents, frequent hand washing, inadequate drying, climate extremes, pre-existing dermatitis, aggressive scrubbing techniques, and glove powders. This reaction is simply an irritation of the skin and should not be confused with an allergy. Symptoms can include redness, chapping, chafing, dryness, scaling, cracking, and subjective symptoms such as itching and burning. An irritant contact dermatitis is a surface condition affecting the skin. Avoiding contact with the irritants, including glove powders, and a regular regimen of proper skin care will help keep hands healthier and free of irritation. Damaged skin more often harbors increased numbers of pathogens. Moreover, washing damaged skin is less effective at reducing numbers of bacteria than washing normal skin, and the number of organisms shed from damaged skin is often higher than from healthy skin. Moisturizing is beneficial for skin health and reducing microbial dispersion from the skin. To improve the skin condition of healthcare workers and reduce their chances of harboring and shedding microorganisms, the following measures are recommended: 1) For damaged skin, mild, nonantimicrobial skin cleansing products may be used to remove dirt and debris. If antimicrobial action is needed (before invasive procedures or handling of highly susceptible patients), a waterless, alcohol-based product may be used. 2) In clinical areas such as the operating room and neonatal and transplant units, shorter, less traumatic washing regimens may be employed instead of lengthy scrub protocols with brushes or other harsh mechanical actions. 3) Effective skin emollients or barrier creams may be used in skin-care regimens and procedures for staff (and possibly patients as well). 4) Skin moisturizing products should be carefully assessed for compatibility with any topical antimicrobial products being used and for physiological effects on the skin. PHYSIOLOGY OF THE IMMUNE RESPONSE The immune response is activated whenever the body is invaded by a foreign body or outside agent. The invader is most often a protein, called an antigen. The body responds by producing natural antibodies called gamma globulins. The antibodies are developed in the lymphoid tissues (lymph nodes) and the reticuloendothelial (immune producing) system and display similar chemical properties to those found in the naturally occurring gamma globulins. Almost all antibodies are gamma globulin molecules. It has been calculated that each plasma cell (which form antibodies) can produce at least 100 molecules of the antibody per second. The gamma globulin (antibodies) reacts with the invading agents and destroys or inactivates them before they can cause damage. There are two immune response reactions associated with natural rubber latex: Delayed Contact Dermatitis-Type IV and Immediate Type 1 Response Latex Allergy. DELAYED CONTACT DERMATITIS — TYPE IV The usual delayed hypersensitivity reaction of allergic contact dermatitis is caused not by latex, but by the chemicals added during rubber manufacture. These chemicals were recognized as problematic more than 50 years ago, as reactions were being caused by exposure not just to latex gloves, but also to many other types of rubber products. Clinically, a red, raised, and palpable area at, and sometimes slightly beyond, the area of contact with the glove is observed, accompanied by subjective symptoms such as itching, burning, and tingling. The mechanism for the development of a delayed response requires the antigen to penetrate the skin, where it then interacts with the cellular components of the immune system. This results in the production of cells of a certain sub-population of the immune system (T-Lymphocytes), which are able to “recognize” the antigen as “foreign”. These effects typically appear anywhere from 6-48 hours following exposure to the antigencontaining product, and can last for up to 4 days. Use of latex gloves while you have active, open breaks in the skin is believed to contribute to latex protein sensitization. This is due to absorption of solubilized latex proteins associated with the product. A return to latex gloves can be made after the open breaks in the skin have healed. A healthcare provider experienced in chemical allergy testing can make the diagnosis by patch testing or skin prick testing, the two tests commonly used to determine the offending chemical. With this information and the assistance of your glove expert, you can usually find a glove that has had the chemical “washed” or “leached” significantly enough from the surface of the glove to be worn successfully, or you may select a different glove that has been manufactured without the offending chemical. Prolonged exposure to the causative agent can lead to a chronic condition characterized by dry, cracked, and scaly skin. When re-exposed to the antigen, these cells stimulate the local release of a number of compounds, including inflammatory agents, resulting in the clinical response described previously. IMMEDIATE TYPE I RESPONSE LATEX ALLERGY Nutter first reported this immune reaction in 1979. It is not solely the result of exposure to gloves, but also to other natural rubber latex-based products such as condoms, balloons, rubber nipples, and other latex medical equipment. While much less common than delayed reactions, the immediate allergic response has received more attention, both from researchers and in the literature, because of its potentially more serious outcome. In the majority of cases reported, the only symptoms are a swelling and redness (commonly described as a “wheal and flare” reaction) local to the site of exposure, accompanied by non-specific symptoms such as itching and burning. In contrast to a delayed response, an immediate reaction can occur almost instantly (within 30 minutes) following exposure to the relevant antigen. The symptoms can spread to areas remote from the site of contact with the glove, and can be accompanied by others such as conjunctivitis, rhinitis, and bronchial obstruction. More seriously, and fortunately more rarely, symptoms of anaphylaxis, and in extreme cases, anaphylactic shock, can occur. The route of exposure for NRL allergens can include: Skin absorption/skin contact with NRL products like gloves. Inhalation/aerosolization of latex proteins bound to glove powder that occurs with donning and removing powdered gloves. Latex allergens are suspended in the air as aeroallergens. Mucosal contact, including eye, nose, mouth, urethra, rectum, and vagina. Intravenous absorption from syringes, IV catheters, central line catheters, and arterial catheters. Ingestion from eating foods without proper handwashing after contact with NRL proteins or eating food that has been handled with latex gloves.

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