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.     

The determination of opiates by latex agglutination

A method based on latex agglutination test has been developed for detection of opiates in human urine. Specific reagents were synthesized and conditions of interaction of conjugated latex antigens with specific antibodies to morphine in the presence of an inhibitor were examined. Sensitivity of the method was 100 ng/ml. The developed latex agglutination test for detection of opiates may be used in combination with enzyme immunoassay in practical forensic medicine and narcology.     

Practitioner and student latex exposure and allergy

Greater application of universal precautions has increased practitioner exposure to chemicals present in personal protective equipment. Of prime concern is the latex present in examination and surgical gloves. A survey concerning latex exposure, allergies, and handwashing was administered to three advanced classes of dental students and was sent to 300 private practitioners in Central Indiana. Results indicate that adverse skin reactions to latex start while in dental school. Problems due to latex gloves were reported by 18.6 percent of the students. Student handwashing materials and methods were adequate, except for inadequate washing time. Adverse skin reactions were reported by 24.1 percent of practitioners wearing latex gloves. Two handwashing problems were noted--inadequate washing time and the common use of water instead of an antimicrobial soap after glove removal. Both students and practitioners reported relatively high levels of personal and family histories of allergy to a variety of sources.     

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.     

Occupational asthma in a latex doll manufacturing plant

BACKGROUND: Occupational asthma caused by latex has been reported in health care workers and workers in glove manufacturing plants. OBJECTIVE: We report occupational asthma from latex in a newly identified occupational setting, a latex doll manufacturing plant. METHODS: We evaluated an index case of asthma associated with work in a latex doll manufacturing plant by performing a workplace challenge and evaluating the work environment. We then performed an occupational survey and skin testing of 22 workers in the doll manufacturing plant. RESULTS: The patient, a 21-year-old woman, had severe immediate bronchospasm within minutes of beginning a workplace challenge where sanding of latex parts was performed. Two of 22 workers surveyed (including the patient) reported flushing, rhinoconjunctivitis, and wheezing on exposure to sanded doll parts. These two workers were the only subjects surveyed to have a history of atopy and positive immediate-type skin test responses to a raw latex extract and to common aeroallergens. CONCLUSIONS: Sanding or grinding of solid latex during the manufacturing process may result in a significant incidence of occupational asthma and rhinoconjunctivitis from latex sensitization. Atopic workers appear to be most susceptible to developing latex sensitivity in this setting.     

Latex contact urticaria and prick test with latex extract

Latex contact urticaria is being reported with increasing frequency. Atopic patients with dermatitis of the hands are at risk of developing this potentially life threatening allergy. Since 1994 we have tested 200 patients in our dermatological department using the latex skin prick test. 20 relevant, positive latex tests have been found. Glove tests and latex-RAST were performed where these were indicated. The diagnosis of latex contact urticaria would have been overlooked in nine patients had the latex prick test not been performed. The clinical manifestations and findings in 24 patients with latex contact urticaria are presented. 12 out of 20 adult patients were not in jobs related to health care. All adults were female, but among the children there were three boys.     

Prospective study of risk factors in natural rubber latex hypersensitivity

Five hundred sixty-nine subjects routinely underwent skin prick tests for latent sensitization to latex. The study of risk factors included skin tests to inhalant allergens, to diagnose atopy, and a questionnaire aimed at revealing frequent exposure to latex such as the wearing of gloves, multiple surgical procedures, or urinary catheterization. The subjects were categorized into five groups: group I, subjects with no risk factor (n = 272); group II, nonatopic subjects exposed to latex (n = 73); group III, atopic subjects not exposed (n = 180); group IV, exposed atopic subjects (n = 44); and group V, subjects with a history of intraoperative anaphylactic shock caused by latex (n = 13). Twenty-five subjects had spina bifida and were in either group II (14 subjects) or group IV (11 subjects). The questionnaire identified a probable allergy to latex in 18 subjects: 16 cases were confirmed by skin test, but responses were not informative in 23 patients who were sensitive to latex. Positive prick tests to latex were obtained in 0.37% of group I, 6.85% of group II, 9.44% of group III, and 36.36% of group IV. Of the children with spina bifida, 32% had positive skin test results. As risk factors, atopy and exposure were synergistic. We recommend predictive prick tests not only in children with spina bifida but also in any atopic subject or in any patient with a history of frequent exposure to latex. Latex could be considered a habitual allergen. The use of latex urinary catheters should be avoided in patients who are catheterized on a daily basis.     

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.     

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.     

Issues and answers in latex sensitivity

Latex sensitivity is a problem for many healthcare professionals. Latex is found in numerous items that a healthcare professional uses on a daily basis, including gloves, tapes, bandages, and catheters. Latex sensitivity can appear as a mild, localized contact reaction, or, in extreme cases, have more sever, systemic effects. Latex not only has the potential to affect a healthcare professional's career, but it can also adversely affect the healthcare professional's life. Several agencies have responded to the increased prevalence of latex-related illnesses, including the Food and Drug Administration and the Centers for Disease Control and Prevention. Lack of a national database and l lack of a government policy mandating the labeling of latex-containing products are just some of the problems that hinder latex research. While there are many unanswered questions regarding latex sensitivity, there are several steps that a healthcare professional can take to protect himself or herself from latex. These include: proper documentation and treatment, preventive measures such as wearing a medical alert tag or bracelet, finding and using latex alternatives in the workplace, and setting up official latex policies within their facilities.     

Detection of plaque-forming cells by a latex bead technique

A new latex bead technique for measuring the plaque-forming cell (PFC) responses to bacterial antigens is described. This technique has been designed for the study of antigens that cannot be readily coated onto SRBC but may also used for antigens that adsorb onto SRBC as well. Application of the latex based technique for the study of PFC response of hamsters to Treponema reiter antigen is described in detail. Using SIII, an antigen that readily adsorbs to SRBC, we have compared the latex bead technique and the conventional SRBC-PFC technique and found that the latex bead technique is more sensitive than the conventional technique. The technique can be used for direct and indirect PFC assays. Technical details for the optimal performance of the latex bead PFC assay are outlined.     

The prevalence of atopy and hypersensitivity to latex in medical laboratory technologists

Members of the Alberta Society of Medical Laboratory Technologists were invited to take part in a study of sensitivity to latex gloves. A total of 230 persons volunteered; 108 (47%) had no problems with gloves, and 122 (53%) reacted to latex gloves. A history was obtained regarding atopy, smoking, years in laboratory medicine, and the nature of the problem with latex gloves. Serum was assayed for the total IgE level and the presence of IgE with specificity to common inhalant allergens and to latex. The affected group had an increased population of subjects with an atopic history and a higher incidence of a raised IgE level and a positive screen for inhalant allergens. In the affected group, there was no relationship between the total IgE level and severity of skin reaction. However, smoking was related to severity of reaction and was more common in the groups with a more severe reaction. Three subjects were positive for IgE specific for latex; there were no other data distinguishing them from latex-negative subjects.     

Type I allergies to latex and the aeroallergenic problem

Between 1989 and 1995, a 12-fold increase in latex allergy was documented amongst our patients. Similar findings have been noted elsewhere. Increase in type I allergies to latex has become an international problem. The issues associated with latex allergy are described, including those posed by the ubiquitous nature of latex in medical equipment, and in commonplace domestic objects. The potential for allergic patients to cross react to a variety of fruits or plants is an added problem for sensitized patients. This paper concludes that the universal introduction of powder-free surgical gloves with low protein content would be a very important measure in the prevention of acquired latex allergy.     

Diagnosis of natural rubber latex allergy: multicenter latex skin testing efficacy study. Multicenter Latex Skin Testing Study Task Force

BACKGROUND: No characterized diagnostic natural rubber latex skin testing material is licensed for use in the United States. OBJECTIVE: We have conducted a multicenter clinical skin testing study to document the safety and diagnostic sensitivity and specificity of a candidate Hevea brasiliensis nonammoniated latex (NAL) extract. These data are intended to support the licensing of this reagent for the diagnosis of latex allergy in high-risk populations. METHODS: Three hundred twenty-four subjects (304 adults and 20 children) were classified by their clinical history as having latex allergy (LA group, 124 adults and 10 children) or having no latex allergy (NLA group, 180 adults and 10 children). All subjects provided blood samples and then received sequential puncture skin tests (PSTs) at 1, 100, or 1000 microg/mL protein with a bifurcated needle and NAL (Greer Laboratories) from Malaysian Hevea brasiliensis (clone 600) sap. A 2-stage glove provocation test was used to clarify latex allergy status of individuals with positive history/negative PST result and negative history/positive PST result mismatches. RESULTS: Twenty-four subjects (15%) originally designated as having LA on the basis of their initial clinical history were reclassified to the NLA group on the basis of a negative glove provocation test result. Of the 134 subjects with LA, 54 (40%) were highly sensitive to latex, with a positive PST result at 1 microg/mL NAL. The Greer NAL reagent produced a positive PST rate (sensitivity) of 95% and 99% in subjects with LA at 100 microg/mL and 1 mg/mL, respectively. The negative PST rate (specificity) in 190 subjects with a negative history with the NAL extract at 100 microg/mL and 1 mg/mL, was 100% and 96%, respectively. Immediately after the PST, mild systemic reactions (mainly pruritus) were recorded in 16.1 % of the adults in the LA group and 4.4% of the adults in the NLA group. No reactions required treatment with epinephrine. Only mild delayed reactions were observed in 9.6% (LA group) and 2.8% (NLA group) of subjects 24 to 48 hours after PST. Mean wheal and erythema diameters measured in the 10 children in the LA group with spina bifida at 100 microg/mL and 1 mg/mL were similar to those observed in the adults in the LA group, suggesting that children are not at increased risk for systemic reactions compared with adults. CONCLUSIONS: A suggestive clinical history is necessary but not sufficient for a definitive diagnosis of IgE-dependent latex allergy. These data support the safety and diagnostic efficacy of the Greer NAL, skin test reagent at 100 micro/mL and 1 mg/mL for confirmatory PSTs.     

Rubber latex allergy and the endodontic patient

Increasingly, patients with rubber latex allergy are being seen in dental offices. Health care workers, persons allergic to certain foods and those with certain medical histories are potentially latex-sensitive. This article presents the case of a patient with a history of severe rubber latex allergy and the associated management of an endodontically involved tooth. The possibility of the latex allergic patient being sensitive to gutta-percha obturation material is also raised.     

In vivo and vitro in diagnosis of latex allergy at Groote Schuur Hospital

OBJECTIVE: The aim of this study was to evaluate the diagnostic utility of skin-prick tests, radio-allergosorbent tests (CAP RASTs), basophil histamine release, sulphidoleukotriene release and Western blotting in the diagnosis of latex allergy at Groote Schuur Hospital. DESIGN: Patients with a history suggesting latex hypersensitivity were recruited via staff health and allergy clinics at Groote Schuur Hospital. A clinical assessment was followed by laboratory investigation and skin-prick testing. A control group consisted of laboratory and hospital staff who had regular latex exposure but were asymptomatic. SETTING: Hospital-based cohort at Groote Schuur Hospital. PARTICIPANTS: Twenty-three patients with suspected latex allergy; 10 control subjects exposed to, but not clinically sensitive to, latex. MAIN OUTCOME: Skin-prick testing was more sensitive than in vitro diagnostic tests for the diagnosis of latex allergy. RESULTS: Eighteen of 21 (85.7%) of the patients tested had a positive skin-prick test with a commercial latex solution (Allerbioprick) and 17/21 (80%) tested skin-prick-positive with an in-house glove extract. CAP RASTs were positive in 13/23 patients (56.5%), sulphidoleukotriene release was positive in 10/23 (43%), histamine release assay was positive in 10/23 (45%) and Western blots were positive in 8/23 (34.7%). All patients with only urticaria were Western blot-negative and CAP RAST-negative, suggesting that they have very little circulating latex-specific IgE. Although patients who were Western blot-positive tended to have multi-organ involvement, both patients with anaphylaxis were Western blot-negative. CONCLUSION: Latex allergy is a significant clinical problem at Groote Schuur Hospital. Titrated skin-prick testing performed in a controlled environment can safely and reliably confirm the diagnosis in patients who do not give a history of anaphylaxis. The CAP RAST was the most sensitive in vitro test for latex allergy locally available, but lacks sensitivity in patients presenting with urticaria only.     

Diagnostic criteria for latex allergy

The author has made an observation which seems to illustrate his proposition perfectly. A patient who was the victim of many acute episodes of rhino-conjunctivitis and severe Quincke's oedema has found benefit from two specialised assessments which established a diagnosis of allergy only to latex. The key to this diagnosis rested on unusual reasoning based on a search for a sufficiently "virulent" allergen to be responsible for the severity of the clinical signs. This idea and recent understanding of crossed allergy materials should aid detection of subjects who are allergic to natural latex.     

A rapid latex agglutination assay for the detection of penicillin-binding protein 2'

A simple and rapid slide latex agglutination assay was developed to detect penicillin-binding protein 2' (PBP2') from isolates of staphylococi. PBP2' present in the membranes of methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-resistant coagulase negative staphylococci (MRCNS) was rapidly extracted by alkaline treatment and, by combining with a slide agglutination reaction using latex particles sensitized with monoclonal antibodies raised against it, PBP2' could be detected from a single loopful of cells taken from agar plates not containing beta-lactum antibiotics within 15 min. In a study of clinical isolates previously characterized as either MRSA or methicillin-susceptible Staphylococcus aureus (MSSA) by antibiotic susceptibility testing, 231 specimens of 232 MRSA were PBP2' positive by latex agglutination, and the 87 specimens of MSSA were all negative. One specimen identified as MRSA by susceptibility testing but PBP2' negative by latex agglutination was confirmed as mecA gene negative by PCR. This simple and rapid slide latex reagent should be useful in clinical diagnostics.     

Cloning, expression and characterization of the major latex allergen prohevein

BACKGROUND: About 70-80% of latex allergic health care workers are sensitized to prohevein (Hev b 6.01), a 20 kDa cysteine-rich chitin-binding protein of Hevea latex. OBJECTIVE: This study reports on the bacterial cloning, expression and immunochemical characterization of rHev b 6.01. METHODS: Prohevein was expressed in the periplasmatic space of Escherichia coli as maltose binding protein (MBP) fusion protein and purified to homogeneity after factor Xa cleavage. The IgE binding capacity of both rHev b 6.01 and prohevein isolated from fresh Hevea latex was compared by immunoblotting experiments using sera of latex-allergic patients. The diagnostic value of rHev b 6.01 was analysed by enzyme allergosorbent test (EAST). RESULTS: Two different cDNA clones of rHev b 6.01 were established. The deduced amino acid sequence of both clones revealed two and three amino acid differences in the C-terminal domain of prohevein compared with the original database entry. Purified rHev b 6.01 bound with high affinity to chitin as its natural counterpart isolated from natural latex. In IgE-immunblotting using sera of affected subjects binding intensity to both proteins was comparable indicating a very high antigenic similarity. The diagnostic value of MBP-prohevein was tested in EAST using sera of 33 latex-allergic subjects. The in vitro test showed high sensitivity and specificity and proved the diagnostic value of uncleaved MBP-prohevein. CONCLUSIONS: The production of recombinant latex key allergens with defined quality like prohevein is a straightforward strategy for the development of standardized in vitro test systems.     

Reversed passive latex agglutination assay for detection of toxigenic Corynebacterium diphtheriae

A reversed passive latex agglutination (RPLA) assay for determining the toxigenicity of Corynebacterium diphtheriae is presented. Rabbit antitoxin antiserum was raised by using commercially available diphtheria toxoid. This antiserum reacted with the diphtheria toxin when the culture supernatant was assayed by Western blotting, and it did not cross-react with other extracellular antigens. Affinity-purified antibodies for latex sensitization were obtained by using a Hi Trap N-hydroxysuccinimide-activated column. Demonstration of toxin in five of seven clinical isolates was in accordance with the PCR assay and the Vero cell cytotoxicity test. Culture of the bacteria for 6 h was sufficient for toxin production, and an additional 6 h was needed to observe latex agglutination. Therefore, diphtheria toxin can be detected in 12 h by this method. The lowest concentration of diphtheria toxin detectable by the RPLA assay was about 5 ng/ml. The RPLA assay can provide a convenient and reliable method for laboratories involved in the identification of toxinogenic corynebacteria.