Clinical Assessment and Effective Management of Latex Allergy

First published in Surgical Services Management, March 1998
D. Sosovec, G. Bourne, D. Davis

Allergy to latex is like any other allergy. Almost everyone, including people who work in healthcare environments, is surrounded by latex--but that does not mean everyone will develop an allergy to latex. Even so, managing latex sensitivities among staff members and addressing the needs of latex-sensitive patients are key issues for healthcare institutions.

Latex in Healthcare Environments

Latex gloves have been used since 1889.1 They are safe, effective, and economical barriers, have excellent tactile properties, and provide superior fit. Natural rubber latex (NRL) gloves are the first line of defense against contagious diseases for healthcare workers and patients. In response to healthcare professionals? reports of allergies to latex during the past few years, manufacturers began to design effective, environmentally safe, and affordable improvements. Today?s gloves offer effective barrier protection and contain historically low levels of the proteins researchers suspect to be allergens.

Prevalence of Latex Allergy

The third National Health and Nutrition Examination Survey (NHANES III) was conducted between 1988 and 1991 with a nationwide sample of approximately 40,000 people. This survey, which is conducted periodically by the National Center for Health Statistics, is designed to obtain nationally representative information on the health and nutritional status of the U.S. population through interviews and direct physical examinations. The NHANES III data were released in July 1997.

Some of the 30 topics investigated during NHANES III were high blood pressure, obesity, lung disease, HIV, hepatitis, immunization status, diabetes, allergies, and dietary intake. Described as a ?gold standard in data collection,?2 NHANES III is the most complete and comprehensive study of latex sensitivity to date.

Following are some of the NHANES III findings.3

  • Regardless of occupation, one in five American adults is likely to be sensitized to natural rubber. This fact is not surprising because individuals in the general population tend to be sensitized to common allergens at similar rates (e.g., large percentages of the U.S. population are sensitized to ragweed, pollen, and bee venom).
  • Latex sensitivity rates for healthcare workers are no different than rates for workers in other occupations. In fact, automobile mechanics and construction workers appear to have slightly higher rates of latex sensitization than healthcare workers (Table 1).
  • The rate of exhibiting debilitating clinical symptoms of latex allergy is the same for healthcare workers and workers in other occupations.
  • Latex sensitivity rates are no higher for older people or for younger people, suggesting no cumulative effect from latex exposure.

Table 1: Latex Sensitivity Prevalence Rates By Occupation

Occupation Rate (%) Occupation Rate (%)
Information clerks 6.5 Records processing 17.8
Management related 9.4 Health diagnosing, assessment, treating 18.0
Sales reps, finance, business 10.8 Protective service 18.2
Material recording clerks 12.0 Cooks 18.5
Waiters, waitresses 12.2 Supervisors, sales 18.9
Laborers (non-construction) 12.5 Construction 20.5
Misc. administrative support 12.7 Other mechanics, repairers 20.7
Farm operator, manager 12.9 Textile machine operators 21.2
Other professional specialty 13.3 Health service 21.6
Secretaries, stenographers 13.5 Machine operator, assorted materials 22.2
Handlers, equipment cleaners 14.3 Misc. food prep and service 22.6
Personal services 15.7 Freight, stock, material movers 23.5
Engineers, scientists 16.4 Private household occupations 23.9
Technicians, related support 16.4 Construction trades 25.4
Cleaning, building service 16.5 Farm and nursery workers 25.5
Teachers 16.9 Motor vehicle operators 25.5
Sales workers, retail 17.0 Agricultural, forestry, fishing 25.8
Extractive/precision production 17.1 Other transportation/moving 26.3
Fabricators, assemblers 17.3 Vehicle, mobile equipment mechanics and repairers 28.3
Executives, administrators, managers 17.6 Writers, entertainers, athletes 29.1

Of the 40,000 people surveyed, 20,050 participated in the adult (i.e., over 17 years of age) survey and provided blood samples. Of these, 5,524 subjects, representing 40 different occupations and including 176 healthcare workers, were tested for latex allergies. Occupations within the category of ?healthcare worker? included RN, physician, dentist, veterinarian, podiatrist, pharmacist, dietitian, dental assistant, nursing aide, orderly, and attendant.

Serum samples were assayed with the DPC AlaSTAT test developed by the Diagnostic Products Corp., Los Angeles. The DPC AlaSTAT was the first test to receive U.S. Food and Drug Administration (FDA) approval, and measures the level of NRL specific IgE antibodies in blood serum. Certain genetically predisposed people may create IgE antibodies specific to rubber when exposed to enough natural rubber protein allergens. This level is unique to each genetically predisposed person. Sensitization is measured by the production of enough natural rubber-specific IgE to test positive on the DPC AlaSTAT test. A sensitized person may or may not have an allergic reaction to rubber; in fact, most sensitized people do not have allergic reactions to rubber.

Responses to questions regarding asthma also were analyzed because asthma is a symptom sometimes reported by people with rubber allergies. Healthcare workers who wear gloves have the same rate of asthma as workers in other occupations. Healthcare workers age 20 and older develop asthma at the same rate as workers in other occupations.

In Brief

  • Latex allergy, though serious, is a manageable issue.
  • Surgical services managers must understand the prevalence and risk of latex allergy among healthcare workers and patients.
  • >This article provides an overview of the latest research in the rates of latex allergy, explains the various tests for determining latex allergy, and outlines the need for assessment, management, education, and avoidance when dealing with latex allergic individuals.

Test Methods

Concerns about latex sensitivity led to the development of different protein and immunological assays (Table 2). These standardized tests measure protein and allergen levels of human serum or extracts of latex products, and they can be useful in making clinical diagnoses and informed product selection decisions. The science underlying these methods is evolving rapidly, and results can vary widely, even within the same test, depending on the test laboratory, the units of measurement, laboratory technicians, the serum pool, and the type of test.

Table 2: Summary of Methods

Test Method Advantages Drawbacks Test Type Factor Quantified Measurement Indicator Limits of Sensitivity
Lowry
  • Commer-
    cially avail-
    able kits
  • Easy to perform
  • Rapid results
  • Not sensitive
  • Many chemical inter-
    ferences skew results
  • Lacks specificity
Colori-
metric
Total protein Chemicals react with all proteins to produce a color change Approxi-
mately 10 g per mL (50 g/gram is the lowest label claim permitted by FDA)
Latex ELISA for antigenic protein (LEAP)
  • Specific to latex antigens
  • Serum is plentiful and homo-
    genous
  • No hazar-
    dous materials
  • Not specific to type I latex allergens (i.e., reacts with all latex proteins)
Serologic; indirect ELISA Antigenic proteins Color change produced by substrate interaction 15 ng per mL
Radio- allergo- sorbent test (RAST)
  • Specific to latex allergen serum from known type I allergic subjects
  • Very sensitive
  • Hetero-
    geneity of serum pool
  • Relative scarcity of human sera
  • Potentially biohazar-
    dous human sera used
Serologic; competi-
tive inhibition
Allergenic proteins Radio-
isotopes (linked to allergen-
antibody complexes)
3 ng per mL
Skin prick
  • Very sensitive
  • Specific to the individual
  • Subjective grading of reactions
  • Itching or greater reaction
  • False negatives
In vivo (Not quanti-
tative biologic reactivity)
Wheal and flare Approxi-
mately same sensitivity as RAST

Lowry Assay

The total protein assay currently recognized by the FDA is the modified Lowry assay (ASTM D 5712-95). This colorimetric method involves extracting residual water-soluble proteins and a precipitation procedure.4 The assay is relatively insensitive and is subject to interference from chemicals that may be added to gloves to enhance their physical properties (e.g., stabilizers, antioxidants, coagulant chemicals). About 135 different chemicals can interfere with the Lowry test, and interference may cause false results (i.e., higher or lower than actual proteins).5 Currently, the lowest water-extractable protein label claim acceptable to the FDA is 50 g or less of protein per gram of NRL. Healthcare professionals should understand that not all proteins from the rubber tree (i.e., Hevea brasiliensis) are equally antigenic (i.e., allergy generating). Gloves can have high protein but low allergen levels and vice versa. Also, the amount of latex allergen exposure required to produce sensitization in an individual, or to elicit reactions in already sensitized individuals, is unknown.

Latex ELISA for Antigenic Protein LEAP

The LEAP is an indirect enzyme-linked immunosorbent assay (ELISA) for natural rubber latex proteins.6 This assay has not been adopted by the American Society for Testing and Materials (ASTM) as a standard method and is not being considered by the FDA at this time. Latex hypersensitivity in humans is based on IgE antibodies reacting to a limited subset of rubber tree proteins. The LEAP assay is based on the binding of rabbit antiserum to proteins isolated from an NRL-producing tree. The LEAP antiserum is produced by injecting rabbits with proteins extracted from rubber tree sap. The reactive rabbit antibodies (IgG) bind to nearly all of the proteins isolated from the rubber tree. Extracts of NRL products are incubated in 96-well polystyrene plates to bind the protein to the plate surface. The rabbit antibody then binds to the protein on the plate. An enzyme is attached to the rabbit antibody by a secondary antibody, and a colorimetric assay is performed. The degree of color will correlate to the amount of NRL protein in the original sample. The results are expressed as g of protein per gram of NRL product. The range of the assay is approximately 0.36 to 6 g per gram of product. Small variations between gloves from different manufacturers may not be significant, particularly if the assays were done in different laboratories.

Radioallergosorbent Test (RAST)--Competitive Inhibition RAST

The RAST is an allergen-specific protein assay that detects and quantifies IgE antibody in human serum samples.7 The allergenic proteins are bound to a surface, and then plasma is allowed to react with the allergens. If there is IgE in the plasma against that allergen, it will bind to the surface. A labeled animal antibody against human IgE is then allowed to bind to any IgE on the surface. If the label is radioactive, it is a RAST assay. If the label is an enzyme, it is a colorimetric ELISA assay (Figure 1).

If no IgE is present, the labeled anti-IgE antibody will be washed away. If IgE is present, a signal will result. When used with the pooled serum of known latex-allergic individuals, this assay can measure antigenic proteins from extracts of products that contain NRL. The anti-latex IgE from the pooled sera binds to the antigenic latex proteins that are isolated from the product containing latex. Because the IgE is already bound to the extract proteins, it cannot bind to the allergenic proteins from the assay kit. Hence, the assay is competitive and results in a decrease in signal if the extract contains the allergens. The source of pooled allergic patient plasma can affect the test outcome and relevancy because allergic individuals can react to different NRL proteins.

Skin Prick Test

Allergy skin testing is the most useful addition to a thorough history emphasizing cause and effect relationships between exposure to potential allergens and symptoms.8 Skin testing generally is performed for one of three reasons:

  • To clarify historical information and identify which of several possible allergens may be causing symptoms
  • To detect allergens that may not be suggested by the history
  • To confirm the presence of specific IgE antibodies before any course of treatment

Allergy skin testing is used to determine the potency of a compound by its effect. Skin testing can specifically identify antibodies (immunoglobulin) capable of precipitating a type I immediate hypersensitivity reaction in a particular individual.

Skin tests may be carried out in a number of ways. One approach is to abrade the skin and place a drop of a concentrated solution of antigen extracts onto the abrasion (scratch test) or to push the antigen into the skin with a sharp probe (puncture or prick test). Another approach is to inject a small bleb of antigen extract 100 times more dilute than the scratch test concentrations under the skin. Test results for both approaches are read in 15 to 20 minutes by determining the mean diameter of any wheals that form. In general, it is not possible to say that a meaningful test should always demonstrate a particular wheal size. Tests always must be interpreted in light of the clinical history--a positive test should never be disregarded. There is no standardized latex antigen extract used for skin prick testing in the United States. Consequently, skin prick test results for latex sensitization may be inconsistent.9

Latex Allergy Management Initiatives

Clinical managers are faced with three major challenges relative to latex allergy:

  • How to identify and provide a safe environment for patients that may have NRL allergies
  • How to determine if an employee may be at increased risk for developing clinical symptoms of NRL allergy
  • How to reasonably accommodate an employee who is diagnosed with an NRL allergy at work.

For both patients and employees, clinical managers should follow a comprehensive, four-step plan that includes assessment, management, education, and avoidance. Developing and implementing well-defined guidelines requires a team approach--a latex allergy committee. This committee should be multidisciplinary with representatives from the medical staff, clinical staff, and ancillary departments (Table 3). Depending on a healthcare facility?s other services and relationships, representatives from ambulatory clinics, free-standing surgery centers, and paramedic providers also may be included on the committee. Many healthcare facilities throughout the United States and Canada have had latex allergy committees in place for several years. In all probability, more than half of all hospitals in the United States now have latex environment guidelines for patient care management.

Multidisciplinary Team

Team members should include the following people:

  • Surgical Services Director
  • Surgery Department Chair
  • Anesthesia Department Chair
  • Allergy and Immunology Department Chair
  • Occupational/Employee Health Director
  • Risk Manager
  • Infection Control Manager
  • Materials Manager
  • Pharmacy Director
  • Radiology Director
  • Laboratory Director

Representatives from the following departments also should be included:

  • Dietary
  • Environmental Services
  • Employee Safety
  • Clinical Education
  • Pediatric Services
  • Ambulatory Services
  • Emergency Medicine
  • Admitting
  • Industrial Hygiene

For those healthcare facilities that are planning to develop latex environment guidelines, a wealth of templates and other resources are available. Many of these resources are accessible through professional clinical organizations, healthcare industry partners, and the Internet (see ?Resources? at the end of this article).

Clinical managers should remember that latex sensitivity does not equal latex allergic reactions and clinical illness. All patients should be assessed for latex allergy, as they should for any allergy, before surgical intervention.10 A recent study conducted at the Henry Ford Hospital?s Detroit campus assessed 996 ambulatory surgical patients for latex sensitivity. Of this group, 6.7% (n = 67) were sensitized to latex (i.e., had IgE antibodies against latex in their bloodstream). Of particular significance is the fact that none of the 67 sensitized patients revealed any significant preoperative allergic reactions to latex, none were treated in a latex-controlled environment, and none experienced any perioperative latex allergic episodes.11 Though this and other studies indicate that 6% to 20% of the total population may be sensitized to latex, only one in 20 sensitized individuals experiences actual clinical latex allergy symptoms.12 The number of individuals who experience severe systemic allergic reactions to NRL is extremely small. Nevertheless, surgical services managers must ensure that all patients are appropriately assessed for latex allergy.

Assessment
If a clinician suspects a patient has a latex allergy, further assessment involving an allergist knowledgeable in latex allergy management may be required. Further screening criteria may include using the AlaSTAT assay or another FDA-approved assay to identify serum anti-latex IgE.

Management
Latex management guidelines or other latex precautions are indicated if an NRL allergy diagnosis is suspected. The goal of a management strategy is to create as safe a care environment as possible. Patient care protocols, as outlined and detailed in the Latex Allergy Information Resource Web page (see ?Resources?), are an excellent resource and reference for establishing or revising guidelines and can be tailored to meet any healthcare facility?s needs.

Avoidance and Education
Patients? exposure to supplies and equipment that contain latex can be avoided, or at least greatly reduced, through coordination and facility-wide awareness. In the controlled environment of the OR, these patients can be successfully treated without incident or allergic reactions.

There are more than 40,000 items used in our daily lives that contain latex. Consequently, patients? risk of exposure is greater outside of the healthcare environment than within. A comprehensive patient education program in latex management and avoidance is paramount in the proactive management of patients? latex allergies. A basic maintenance regime for an individual with confirmed NRL allergy should include:

  • Ongoing management by a knowledgeable allergist
  • Identifying products that contain natural rubber latex with which the individual may come in contact
  • Avoiding items that contain natural rubber
  • Maintaining a personal inventory of synthetic gloves
  • Wearing a medical alert bracelet
  • Carrying an autoinjectable syringe of epinephrine

Latex Allergy and Occupational Health Protocols

As the NHANES III and other studies13 report, healthcare workers are not at a greater risk for developing type I NRL allergies than other occupations or the general population. Healthcare workers may be at increased risk for skin reactions, irritations, contact dermatitis, and delayed type IV chemical allergies that have been associated with increased hand washing, lack of hand washing, increased glove use, and inadequate or inappropriate hand care.

How should surgical services managers determine if a staff member is allergic to NRL or is experiencing dry, reddened, irritated skin related to other factors? Healthcare workers who may have latex allergies should be assessed by occupational/employee health services managers. If the employee has an irritation due to factors other than latex, management may include changing soap or scrub solutions, changing gloves, wearing a glove liner, or improving hand care. If the employee is suspect for chemical allergy, a consultation by a dermatologist may be appropriate. If the employee is suspect for type I NRL allergy, consultation by an allergist with further assessment and testing may be indicated (contingent on individual healthcare plans and hospital protocols).

Management Options for Confirmed NRL Allergic Employees
Most healthcare workers who are NRL allergic can continue to work in the clinical setting with minimal restrictions. For most of these individuals, wearing synthetic gloves, avoiding other latex products, and understanding that their exposure to other latex products should be monitored may be all that is required. Work reassignment and job modification or restrictions should be determined in collaboration with the treating allergist, occupational health manager, risk manager, or industrial hygienist, and the surgical services manager. Healthcare facilities need to establish protocols that provide for ?reasonable? work accommodations for these employees (e.g., providing nonlatex gloves for a latex allergic employee). Reasonable accommodations vary from state to state and from hospital to hospital, depending on state worker compensation guidelines, union contracts, and individual hospitals? limitations.

Conclusion

Latex allergy is a very important issue. This allergy is similar to the prevalence of allergies to pollens, bananas, strawberries, peanuts, and other substances. Latex allergy must be managed appropriately--surgical services managers can provide latex-controlled environments for patients and staff members by using comprehensive guidelines and protocols. The good news is that current studies and research help illustrate the scope and course of this phenomenon and show that latex sensitivity is not occupationally induced.14 Future research also should provide effective treatment methodologies. Latex allergy, just as any allergy, can be managed by well informed and knowledgeable healthcare professionals.

1. J.M. Miller, ?William Stewart Halsted and the Use of the Surgical Rubber Glove,? Surgery, 92 (September 1982), 541-543.

2. T. Harris, ?Medical News and Perspectives,? Journal of the American Medical Association, 277 (January 8, 1997), 89-178.

3. National Health and Nutrition Examination Survey, III 1988-1994, Series II, No 1, CD-ROM version 1.22A (Washington, DC: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics, July 1997).

4. ?ASTM D 5712-95: Standard Test Method for Analysis of Protein in Natural Rubber and Its Products,? Annual Book of ASTM Standards, Vol. 14.02 (Conshohocken, PA: American Society for Testing and Materials, 1995).

5. E.M. Davis, ?Protein Assays: A Review of Common Techniques,? American Biotechnology Laboratory 6, No. 5 (1988) 28-37.

6. D.H. Beezhold, ?LEAP: Latex ELISA for Antigenic Proteins, Preliminary Report,? The Guthrie Journal, 61 (Spring 1992), 77-81.

7. D.M. Kemeny, S.J. Challacombe, ELISA and Other Solid Phase Immunoassays: Theoretical and Practical Aspects (New York: John Wiley and Sons, Ltd, 1988).

8. Manual of Clinical Problems in Asthma, Allergy, and Related Disorders, D.A. Bukstein, R.C. Strunk, eds. (Boston: Little Brown, 1984).

9. V.P. Kurup, et. al., ?Immunoglobulin Reactivity to Latex Antigens in the Sera of Patients from Finland and the United States,? Journal of Allergy and Clinical Immunology, 91 (June 1993), 1128-1134.

10. Food and Drug Administration, ?Allergic Reactions to Latex Containing Medical Devices,? FDA Medical Alert, Pub. No. MDA91-1 (March 29, 1991).

11. M.H. Lebenbom-Mansour, et. al., ?The Incidence of Latex Sensitivity in Ambulatory Surgical Patients: A Correlation of Historical Factors with Positive Serum Immunoglobin E Levels,? Anesthesia and Analgesia, 85 (July 1997), 44-49.

12. A. Saxon, ?Latex Allergy Symposium Report.? Speech presented at the International Meeting and Educational Conference of the Association of Professionals in Infection Control, New Orleans, 10 June 1997.

13. M. Grzybowski, et. al., ?The Prevalence of Anti-Latex IgE Antibodies Among Registered Nurses,? Journal of Allergy and Clinical Immunology, 98 (September 1996), 535-544.

14. National Health and Nutritional Examination Survey, III 1988-1994, Series II, No 1, CD-ROM Version 1.22A.

Resources

American Association of Nurse Anesthetists
Latex Allergy Protocol
222 S. Prospect Ave.
Park Ridge, IL 60068
http://www.AANA.com

Latex Allergy Recognition Protocol
Hand Care Protocol
Latex Allergy Updates
Cardinal Health, Professional Services
1500 Waukegan Rd.
McGaw Park, IL 60085-6787
(800) 327-7503
http://www.cardinal.com/mps

How to Manage a Latex-Allergic Patient
The Latex Allergy Information Resource
http://www.anesth.com/lair/lair.htm

Supported by the Department of Anesthesiology at Case Western Reserve University, Cleveland.

Diane Sosovec, RN, MS, CNAA, is manager, clincial resources, for Cardinal Health, McGaw Park, IL

George Bourne, MS, MBA, is vice president, research and development, for Cardinal Health, McGaw Park, IL

Deborah Davis, MS, MBA, is technical director, Cardinal Health, McGaw Park, IL
Phone: (847) 692-7050
Fax: (847) 692-6968