Setting standards for product selection: allergy prevention

It is axiomatic to state that if products made of natural rubber latex were not used in health care settings then there would be no problems of acquired hypersensitivity from such products. Although synthetic materials are available they do not currently possess the same technical qualities of elasticity and comfort, nor do they deliver the desired degree of protection against biological agents as gloves made out of natural rubber latex. Selection of gloves either for non-sterile procedures or sterile surgical use should be based on this understanding, and gloves with minimal levels of extractable latex proteins should be used.     

Occupational asthma due to latex in health care workers

Immediate hypersensitivity reactions ranging from mild urticaria to life threatening anaphylaxis after exposure to natural rubber latex have been reported frequently in health care workers while occupational asthma due to latex exposure is less well studied. The results of specific challenge tests and immunological tests in four health care workers with work related respiratory and skin disorders induced by the use of latex gloves are described. Occupational asthma was confirmed in three subjects by specific challenge tests. All had a positive skin test reaction to the latex extract; specific IgE antibodies were detected in only one subject. The fourth subject had a negative specific inhalation and skin test reaction to the latex extract. Peak expiratory flow monitoring at work and away from work showed a pattern consistent with work related asthma. These findings confirm that latex is a cause of occupational asthma in health care workers.     

Latex allergens: review of current knowledge

Both health care workers and spina bifida patients are at risk to develop type I latex allergy since allergenic proteins of natural rubber latex are present in a variety of latex products. Natural latex contains more than 250 polypeptides and approximately 60 of them show IgE-binding characteristics. A multitude of these latex allergens has been identified, and their sensitization potency for both risk groups has been determined. While hevein (Hev b 6.02) is the major allergen in latex-allergic health care workers, 80% of latex sensitized-spina bifida children have IgE antibodies to the "rubber elongation factor" (Hev b 1). Almost all relevant latex allergens have been identified in natural latex products: however, no data on the allergen profiles of individual latex products exist. The knowledge of the major latex allergens enables improved diagnosis and to monitor the success of prevention strategies for decreasing the high prevalence of latex allergies.     

Protein affinity map of chemical space

Natural latex from the rubber tree Hevea brasiliensis is an allergen in persons with significant cumulative latex exposure, such as those in the health care and rubber industries, as well as those undergoing repeated surgeries, especially if they undergo surgeries early in life. Symptoms of latex allergy may progress rapidly and unpredictably to anaphylaxis. The prevalence of latex allergy has increased as the use of rubber gloves in health care settings has increased. Airborne latex particles that adhere to the cornstarch used to powder gloves are a significant cause of respiratory symptoms and a source of sensitization. Once an individual has become sensitized, he or she may experience allergic symptoms when exposed to any product containing latex. Diagnosis is made initially by the history. Latex-specific IgE testing and skin prick testing may confirm the suspicion. The most effective strategy in the treatment of latex allergy is avoidance; however, there is a large group of sensitized people who have not been identified and who do not recognize that their symptoms are caused by latex allergy. Physicians caring for latex-sensitive persons must act as their advocates in building awareness of the problem and developing protocols for their safe care. Latex-sensitized persons should be educated about the latex content of common objects.     

Management of latex reactions in the occupational setting

1. The increased use of natural rubber latex barrier protection to prevent exposure to bloodborne pathogens has led to an increase in latex related health reactions, particularly associated with glove use. 2. The three types of reactions to latex in order of frequency include irritant contact dermatitis, allergic contact dermatitis, and immediate systemic/anaphylaxis reactions. 3. The management goal for all reactions is to avoid unnecessary restriction from the appropriate use of latex (gloves) which provides the best barrier protection, while protecting individual workers from exposure that results in sensitization or causes sensitized individuals to have serious reactions. 4. Choose non-latex gloves when barrier protection from bloodborne pathogens is not an issue. When selecting a latex glove, choose a glove that is low in proteins and powder free to control airborne latex exposure.     

Psychopathological disorders and coronary diseases

BACKGROUND: Endotoxin is an inflammatory made by gram negative bacteria that can irritate the skin, induce respiratory problems, fever, and shock. It is an adjuvant for both delayed hypersensitivity and IgE production and has been shown to magnify antigen specific mediator release. Since many of the clinical problems associated with natural latex products involve similar clinical sequelae, we investigated the possibility that latex gloves might be contaminated with endotoxin. OBJECTIVE: To measure the endotoxin content of a variety of natural latex gloves, investigate the its distribution and origin, associated with latex proteins, and determine the particle sizes associated with its release. METHODS: Endotoxin, protein, and allergen were measured using a quantitative kinetic Limulus assay, modified Lowry, and RAST inhibition, respectively. Particle size and density were determined using an Anderson multistage air sampler and CsCl2 gradient. RESULTS: Endotoxin was found to be a highly significant contaminant of some latex gloves. Levels ranged from 0.09 ng to 2.8 micrograms/g of glove. Protein levels ranged from < 25 to 1150 micrograms/g of glove while allergen levels ranged from < 1 to 837 micrograms/g of glove. Endotoxin and protein eluted rapidly from the interior of the gloves tested. Greater than 70% of the endotoxin was found to be associated with particles in the < 7 microns aerodynamic diameter range. The highest levels of endotoxin were found in nonsterile examination gloves with a tendency towards powdered gloves containing more endotoxin and protein. A slurry containing cross-linked dextran through which gloves were dipped revealed very high endotoxin contamination (64 micrograms/mL) while unused cross-linked dextran has very little associated endotoxin. CONCLUSIONS: These data demonstrate that some natural rubber latex gloves, particularly nonsterile examination gloves, are contaminated with high amounts of endotoxin and proteins. These were found mostly on the inside of gloves and were released as very small respirable particles that were not physically associated with the powder. These findings support the hypothesis that endotoxin may be responsible for some of the tissue irritation associated with latex glove use. In addition, this material may be responsible for the enhancement of delayed and immediate hypersensitivity reactions to chemicals and proteins found in these products and offers a possible explanation for the disproportionate severity of these reactions.     

Examination gloves as barriers to hand contamination in clinical practice

OBJECTIVE: To test the effectiveness of vinyl and latex gloves as barriers to hand contamination with gram-negative organisms and enterococci during routine hospital procedures. DESIGN AND INTERVENTIONS: We studied 137 procedures during which a health care worker's gloved hand contacted a patient's mucous membrane and was thus potentially contaminated with gram-negative rods or enterococci. Quantitative hand cultures were obtained from each health care worker before and after the gloved contact using a modified glove juice method, and the exterior glove surface was also quantitatively cultured after patient contact. Used gloves were then tested for leaks using the American Society for Testing and Materials' watertight test. SETTING: Harborview Medical Center, a 330-bed city-county hospital and level I regional trauma and burn center, is both a teaching facility affiliated with the University of Washington and the major provider of care to indigent and uninsured persons in Seattle-King County, Washington. PATIENTS AND OTHER PARTICIPANTS: Respiratory therapists performing endotracheal tube care on intubated intensive care unit patients, registered nurses performing digital rectal stimulation for bowel training on patients with spinal cord injury in the rehabilitation ward, and dentists performing routine dental examinations and procedures on healthy outpatients in the dental clinic. MAIN OUTCOME MEASURE AND RESULTS: Eighty-six of the 135 gloves cultured had gram-negative rods or enterococci on the external surface after use and were thus sources of potential hand contamination. Microbial contamination of the health care worker's hands occurred in 11 (13%; 95% confidence interval, 6% to 20%) of these 86 events, and was more frequent with vinyl (10 of 42) than latex (one of 44) gloves (P < .01). After use, glove leaks were also more frequent in vinyl gloves (26 of 61) than with latex gloves (six of 70) (P < .001). Even when leaks were present, gloves prevented hand contamination in 77% of instances and quantitative counts of microorganisms contaminating hands were 2 to 4 logs less than counts on external glove surfaces. Health care workers reported awareness of the presence of glove leaks in only seven (22%) of the 32 events in which leaks were subsequently demonstrated. CONCLUSIONS: Under conditions of routine use, gloves effectively function as a protective barrier even when leaks are present. Latex gloves were less frequently associated with leaks and hand contamination. Since hand contamination occurred after 13% of exposures and cannot be readily identified by health care workers, routine hand washing should be done after each patient contact.     

Delayed and immediate orofacial reactions following contact with rubber gloves during dental treatment

Allergic reactions during or after dental examination are uncommon. However, such reactions may be serious and distressing. Allergy to local anaesthetics and dental materials may be considered, but reactions to rubber in gloves worn by the dentist should be remembered. Two patients are reported who experienced symptoms following contact with rubber gloves worn by their dentists, with skin tests subsequently showing an allergic reaction to glove constituents, and in one case latex. With the increasing use of rubber gloves by dental and medical personnel, reactions in sensitised patients are likely to become more common. In patients with a history of symptoms related to dental work, it is important to remember delayed and immediate reactions to rubber.     

The blood coagulation aspects of acute infectious myocarditis]

With the increase in infectious disease epidemics and the need to protect health-care workers, the use of rubber gloves has increased twofold. Recent reports have noted an increase also in the prevalence of natural rubber latex allergy among some of these workers. A newly emerging problem, the allergy has potentially life-threatening consequences for those affected, a fact which has far-reaching ramifications for all those working in contact with latex, critical care nurses in particular. Indeed, the allergy has had a major impact on one such nurse, to the extent that she has had to relinquish her career and make significant changes to her lifestyle. Latex allergy was first recognised in 1927 but has become more prevalent in the last few years. There are two types of reactions, type I and type IV, with symptoms varying from a mild itch to anaphylaxis. Diagnosis is made via a blood or skin test, as well as a patient history. Treatment is to medicate for symptoms, while avoidance is the only way to prevent occurrences. The case study which follows reveals the impact that this allergy can have on a critical care nurse.     

Understanding latex allergy

Latex allergy is an increasingly important problem in both health-care workers and patients. Predisposing factors to development of latex allergies include a history of atopy or allergy and frequent exposure to latex products. Identified allergens include latex proteins from the rubber tree that remain in manufactured products, as well as smaller molecules that remain from the latex purification and manufacturing process. Latex proteins absorbed to powder in latex surgical and examination gloves may be aerosolized and inhaled. Powder-absorbed latex proteins are thought to be important in triggering of sensitization in susceptible individuals, as well as in elicitation of symptoms in previously sensitized patients. Allergic reactions to latex can include local dermal reactions or generalized immediate hypersensitivity (anaphylactic) reactions. Pathophysiology, signs and symptoms, and treatment of each type of reaction are discussed. Measures to address latex allergy, however, must include measures to decrease exposure to latex antigens both in latex-allergic subjects, to prevent symptoms, and in naive subjects, to prevent sensitization. These measures may include finding, acceptable substitutes for latex in many products.     

Sensitivity to latex and other rubber substances--an important occupational risk for health personnel (case report)

Sensitization to latex and rubber additives has been acknowledged during the last 10 years as a major occupational health problem among health-care workers. In sensitized persons, respiratory and/or skin symptoms may be present. Pathophysiologic mechanisms of senzitisation involve allergic reactions types I and IV (Coombs and Gell). In this case report we described a female health-care worker with sensitization to latex and rubber additives simultaneously present on the skin and in the respiratory system, caused by wearing protective rubber gloves. The complex diagnostic procedure involved in determination of occupational allergic diseases is discussed.     

Characteristics of the dysarthria of multiple system atrophy

Allergy to latex has become an increasing and clinically important problem during last years. Natural rubber latex (NRL) allergy has been acknowledged as a major occupation problem among health-care workers. More recently, NRL allergy also occurs in children with spina bifida and in atopic children. Even patients allergic to various fruits, such as banana and avocado may experience allergic reaction from NRL and vice versa. Different latex allergens have been characterized at the molecular level using varied techniques and heterogeneous latex materials. Little is known about prevalence and clinical relevance of latex sensitization and allergy in the general population although the incidence is increasing in children. The wide spectrum of symptoms of NRL allergy range from mild contact urticaria to asthma and anaphylactic reactions. History is an integral part to identify latex allergy. Different tests (skin prick tests, RAST, Pricking, Use test) have been used to objectively supplement the history. Latex allergy must be prevented by the standardization of medical gloves including the labeling of latex content and allergenicity; furthermore the industrial strategies may also develop new methods of less allergenic gloves and other NRL products.     

Latex allergens in tire dust and airborne particles

The prevalence and severity of latex allergy has increased dramatically in the last 15 years due to exposure to natural rubber products. Although historically this health risk has been elevated in hospital personnel and patients, a recent survey has indicated a significant potential risk for the general population. To obtain a wide-spread source for latex exposure, we have considered tire debris. We have searched for the presence of latex allergens in passenger car and truck tire tread, in debris deposited from the atmosphere near a freeway, and in airborne particulate matter samples representative of the entire year 1993 at two sites in the Los Angeles basin (California). After extraction of the samples with phosphate buffered saline, a modified-ELISA inhibition assay was used to measure relative allergen potency and Western blot analyses were used to identify latex allergens. The inhibition studies with the human IgE latex assay revealed inhibition by the tire tread source samples and ambient freeway dust, as well as by control latex sap and latex glove extracts. Levels of extractable latex allergen per unit of protein extracted were about two orders of magnitude lower for tire tread as compared to latex gloves. Western blot analyses using binding of human IgE from latex-sensitive patients showed a band at 34-36 kDa in all tire and ambient samples. Long Beach and Los Angeles, California, air samples showed four additional bands between 50 and 135 kDa. Alternative Western blot analyses using rabbit IgG raised against latex proteins showed a broad band at 30-50 kDa in all samples, with additional bands in the urban air samples similar to the IgE results. A latex cross-reactive material was identified in mountain cedar. In conclusion, the latex allergens or latex cross-reactive material present in sedimented and airborne particulate material, derived from tire debris, and generated by heavy urban vehicle traffic could be important factors in producing latex allergy and asthma symptoms associated with air pollution particles.     

The role of glycosylation in autoimmune disease

Lack of knowledge concerning latex allergy may lead to a life-threatening adverse reaction to natural rubber latex. Registered nurses need a latex allergy knowledge base to provide latex-safe health care to clients and to create a latex-safe environment. This research explored the current knowledge base of registered nurses as related to (1) the care of clients at risk for latex allergy, or diagnosed with latex allergy, and (2) the provision of a latex-safe environment for all populations. This article describes this research and its implications for nurses. A copy of the Latex Allergy Knowledge Base Self-Assessment Questionnaire is included at the conclusion of the article.     

Clinical pharmacokinetics: the basis of laboratory monitoring of drugs (lecture)

The purpose of this article is to educate the dental hygienist about the seriousness of latex allergy and provide background information necessary for treating the latex allergic patient, including basic information on immunology, hypersensitivity reactions, latex, and natural rubber latex. Symptoms of latex allergy, types of reactions, and methods of exposure are discussed. Methods for achieving a minimal latex environment are presented, along with information to treat the patient with latex allergy, which can affect health, career, future, and lifestyle. Because the number of latex-allergic individuals increases daily, a thorough understanding of its diagnosis and implications is necessary for all oral health care workers.     

Latex allergies and adverse reactions: a review of the literature

In the last few years, the allergenic potential of latex has been receiving greater attention. While latex allergies have been widely reported in the literature, the prevalence and severity have rapidly increased in the last few years. The role of rubber in the prevention of HIV infection has played a part in recognizing the allergenic potential, as with increased emphasis on infection control in the dental office has come an increase in complaints of adverse reactions to surgical gloves. A review of the literature reveals latex allergy problems to be not confined to gloves, but to articles of clothing, rubber dam material, and other latex-containing materials. Life-threatening cases have been reported. Little information in the literature concerns the extent of the problem among dental personnel. The dental professional may be faced with not only discomfort for the dental staff, but also compromising reactive possibilities in certain patients. There is a need for development of alternative protective products for the dental office, since elimination of barrier protection is not a viable alternative to infection control.     

Risk assessment of dithiocarbamate accelerator residues in latex-based medical devices: genotoxicity considerations

The Medical Devices Agency (MDA) has investigated potential human health hazards arising from the presence of dithiocarbamate vulcanization accelerators in latex products (mainly gloves). After collection of manufacturer's data on usage and residues of these accelerators, an independent investigation of solvent extractable residues and dithiocarbamate migration into aqueous simulants was commissioned, to complement equivalent "in-house" test data from two major manufacturers. The presence of extractable accelerator residues in commercial products was confirmed. Potential human health hazards associated with dithiocarbamates include genotoxicity and possible carcinogenicity: a review of published data was conducted to evaluate the evidence for this, with particular reference to three zinc dithiocarbamates with significant commercial usage (ZDMC, ZDEC and ZDBC: see Fig. 1). Data gaps were identified, and mutagenicity studies commissioned to fill these. These studies comprised tests both in vitro (bacterial and L5178Y cell gene mutation, cultured lymphocyte chromosome aberration) and in vivo (mouse bone marrow micronucleus, rat liver UDS). It is concluded that ZDMC must be considered a genotoxin (and thus a probable carcinogen): residues of this substance in latex medical devices should be minimized. ZDEC proved genotoxic in vitro but was not clearly genotoxic in vivo, and may have activity intermediate between that of ZDMC and that of ZDBC, which showed at most weak activity in a single in vitro (chromosome aberration) test. It is proposed that the use of ZDBC as a vulcanization accelerator in the manufacture of latex gloves, rather than ZDEC, ZDMC or their precursors, would reduce or remove the health concerns arising from accelerator residues.     

Latex allergy in health services workers

The studies were performed in 20 workers from the Health Service (13 women and 7 men in the age 25-57) suffering from hand urticaria (6 persons) and hand dermatitis (14 persons) suspected of the allergy to latex gloves. In all patients the familial and personal predispositions to allergy were evaluated by the anamnesis, the estimation of total IgE serum level and the skin prick tests (SPT) with inhalant allergens. The latex allergy was diagnosed by SPT and contact test with standardized extract of the natural latex allergen in the concentration 1000 PNU/ml (Nexter-Allergopharma) and by estimation of specific to latex IgE serum level. In addition to this, contact tests with glove's material as well European standard contact allergens (Hermal) were done and the one with antiseptic substances to which the patient was exposed at his work. The allergy type I to latex gloves was confirmed in all 6 cases with contact urticaria. The SPT with standard extract of the natural latex was more valuable than latex specific IgE in the serum. Contact allergy (type IV) to latex gloves was confirmed in 10 from 14 suspected cases. In the next 4 the allergy to antiseptic substances was the reasons of the illness. The allergy to latex gloves appears more often in women. No case showed the familial predisposition to allergy and only 4 patients additionally suffered from the allergy to pollen and mites. Moreover in both groups of patients we showed the presence of the additional contact allergy to different allergens (to metals and antiseptic substances).     

Glove powder--a risk factor for the development of latex allergy?

Studies are described which compare the prevalence of sensitisation against latex proteins in medical personnel in different hospitals. The objective of these studies was to find out whether the use of powdered or unpowdered gloves could be related to the prevalence of latex allergy. Employees of one of the investigated hospitals (Germany) were using only powdered latex gloves, and in the other two hospitals (Great Britain) low protein powder-free latex gloves were used. Methods by which latex allergy can be avoided are suggested.     

Up- and down-regulation of calpain inhibitor polypeptide, calpastatin, in postischemic hippocampus

A dental student developed swelling of the lips and peri-oral urticaria, immediately after placement of a dental rubber dam during a chairside demonstration of clinical dentistry. A provisional diagnosis of a Type I hypersensitivity reaction to natural rubber latex was made and an appointment organised for specialist investigations. The student reported an atopic history and allergy to peanuts. A Radioallergosorbent Test (RAST), to measure Ig-E antibodies to latex, was positive. The dental student was given advice concerning the avoidance of natural rubber latex. Dental staff must be aware of potentially serious reactions to natural rubber latex in the dental surgery.