Patients, health care workers, and latex allergy.

An estimated 40,000 manufactured products contain latex. With increased use has come increased allergies. Here's what to look for and how to avoid problems.

An estimated 40,000 products, used billions of times each year, contain natural rubber latex.[1] As health care workers, we come in contact with latex every day, whether it be through gloves, catheters, intubation tubes, anesthesia masks, blood pressure cuffs, adhesive tape, or tourniquets, just to name a few sources.

Furthermore, there are many latex products commonly found in the home, including pacifiers, balloons, condoms, rubber bands, bails, and toys. See "Harvesting Hevea brasiliensis" on the next page for an explanation of the origin and manufacture of latex products.

* Occupational allergy. The use of latex gloves has grown dramatically due to the increased awareness of AIDS, implementation of universal precautions, and enforcement of other OSHA regulations. This boom in the use of latex products has led to increased reports of latex allergy.

In addition to health care professionals, other groups seem to be at higher risk for latex sensitivity. One of these groups is children with spinal cord injuries such as spina bifida. A 1989 study showed that 10 out of 12 spina bifida patients have severe reactions to latex.[2] These patients undergo multiple surgeries and frequent bladder catheterization, increasing their exposure to latex products.

Latex allergy has been well documented. While the incidence of latex allergy is [less than] 1% in the general nonatopic population,[3] reported cases are highest in patients who undergo multiple surgical procedures, including those with spina bifida, followed by dentists, surgical personnel, and other hospital employees (see Figure 1).

* Severe reactions. On March 29, 1991, the FDA issued a medical alert titled "Allergic Reactions to Latex-Containing Medical Devices."[4] The purpose of the alert was to advise health care workers to be aware of latex allergy and to be prepared to treat attendant reactions promptly. This alert was based on reports of severe allergic reactions to common latex-containing medical devices. The FDA has also published data on the incidence of anaphylactic reactions to several different products containing latex, several of which are listed in Figure 2.

Another cause of increased latex allergy was lack of QC guidelines in glove manufacturing in the mid- to late '80s.[5] With greater demand for latex gloves, many inexperienced manufacturers sacrificed quality for profit, resulting in the manufacture and sale of poor quality gloves containing many potential allergens.

* Highest risk. Latex allergies result from repeated exposure to latex products; sensitization occurs over a long period of time. Latex allergens enter the body through inhalation or by way of cuts or open sores on the hands. Dry, chapped hands, resulting from cold weather or using alcohols and soaps, are common routes of entry.[6]

Patients allergic to latex are at greatest risk for anaphylaxis when there is direct contact between latex and mucosal surfaces. Latex proteins bind to glove starch.[7] Patient contact occurs when glove powder bound with latex proteins, water soluble proteins, and chemicals is transferred from the latex device to patient tissue (in surgery, e.g.). This results in direct inoculation of the antigen, which leads to an IgE-mediated antibody response. Sensitization via glove powders bound with latex protein may cause asthma, allergic rhinitis, sinus problems, or systemic manifestations.[8]

* Types of reactions. There are three major types of reactions to latex: contact dermatitis and types IV and I hypersensitivities.

Contact dermatitis is the most common type of reaction. This is not an allergic reaction involving the immune system, but rather a skin irritation caused by the chemicals added to the latex during manufacturing or by the glove powder itself.[9]

Type IV delayed hyper-sensitivity is the second most common type of latex allergy. This reaction is mediated by T-cells and is characterized by burning, swelling, and the development of debilitating rashes with itching and cracking of the hands. This type of hypersensitivity is also believed to be caused by sensitization to those chemicals added to latex during the manufacturing process.[10] The type IV reaction is comparable to the allergic contact dermatitis caused by poison ivy.

Type I immediate hypersensitivity is the least common and the most serious reaction, one that can be life-threatening. The response is an IgE-mediated anaphylaxis that induces the body to manufacture potent chemical mediators that produce such symptoms as hypotension, urticaria, edema, nausea, vomiting, diarrhea, sneezing, and nasal congestion.[11] Type I immediate hypersensitivity is an immune response to a foreign substance (the latex protein) characterized by the synthesis of IgE, which has a high affinity for mast cells and basophils. When the skin or mucous membranes are reexposed to the allergen(s), IgE bound to the receptors on the surface of the aforementioned cells causes them to degranulate and release histamine, pros-taglandin, leukotrienes, etc.[12]

The presence of latex antigen triggers a cellular response, with subsequent sensitization and antibody production by lymphocytes. The response to latex is shown to be IgE mediated through skin testing, basophil histamine release, RAST, ELISA, and IgE immunoblot.[13,14]

* What's being done? At the present time, researchers and manufacturers of latex products are developing new techniques to remove the offending allergens during manufacture. Low-allergen latex gloves are on the market.[15] Different washing techniques remove latex proteins and maintain a product that has tensile strength and barrier protection. Protein levels are being monitored using protein assays, ELISA, RAST-inhibition, and nesslerization.[16] Makers of latex products continue to maintain lower levels of protein.

What do we do to reduce the risk? The first step is to be aware of the potential dangers of latex allergy. Be alert to the threat of latex allergy and latex-induced anaphylaxis, especially in patients who have had multiple surgeries. All patients, regardless of risk group, should be questioned about a history of latex allergy. We must work hard to provide a latex-free environment for all latex-sensitive patients.[17]

Figure 1

Population distribution for latex allergy in health care

Dentists                     13.7%
OR physicians                 7.5
OR nurses                     5.6
Other hospital employees      1.3

Source: Leynadier F, Pecquet C, Dry J. Anaphylaxis to latex during
surgery. Anaesthesia. July 1989; 44(7): 547-550. Cited in Stehlin D.
Latex allergies: When rubber rubs the wrong way. FDA Consumer.
September 1992; 26(7): 16-21.
Figure 2

Latex-induced anaphylactic reactions by product

Enema tips                     422
Exam gloves                    408
Surgical gloves                 77
Condoms                         53
Tapes/bandages                  32
Vascular catheters              30
Other products                 111

Total reports to date:       1,133
Reported deaths:                15

Source: Food and Drug Administration.

* Life without latex. A latex-free environment includes using nonlatex gloves, catheters, endotracheal tubes, suction tubing, and other such implements. Avoid latex bandages, tourniquets, and blood pressure cuffs. When taking blood from a latex-sensitive patient, wear non-latex gloves and don't take trays of supplies into patients' rooms. Use a cloth tourniquet and latex-free tape/gauze in lieu of latex bandages to help prevent transmission of aerosolized antigens.

Health care workers sensitive to latex should use nonlatex gloves such as those made of polyvinyl chloride or neoprene. These gloves do not provide optimal barrier protection against the transmission of viruses, however. If you do wear latex gloves, limit exposure to its allergens by routinely washing your hands, and avoid touching eyes, nose, or mouth to prevent direct contact with mucous membranes.

Do not use petroleum products or other skin protectants when wearing latex gloves. These substances break down the latex and decrease barrier integrity. Routine use has the same effect.[18] The FDA has suggested wearing a latex glove between two vinyl gloves.[4] If a latex allergy develops, notify your personal health care provider and follow his/her suggestions regarding precautions.

References

1. Stapleton C. The latex scare. Woman's Day. March 2, 1993; 74-75.

2. Banta J, Bonnani C, Prebluda J. Latex anaphylaxis during spinal surgery in children with myelomeningocele. Dev Med Child Neurol. 1993; 35: 540-548.

3. Sussman GL, Beezhold DH. Allergy to latex rubber. Ann Intern Med. 1995; 122: 43-46.

4. Strickland DA. Latex sensitivity prompts alert. Med World News. April 1991: 13.

5. Whitmeyer R. Trends in glove product and process development. Biomed Instrum Technol. May/June 1992; 235-237.

6. Fay M. Hand dermatitis: The role of gloves. AORN J. September 1991; 54(3): 453-467.

7. Beezhold D, Beck W. Surgical glove powder binds latex antigens. Arch Surg. November 1992; 27: 1354-1357.

8. Bubak ME, Reed CE, Fransway AF, et al. Allergic reactions to latex among health care workers. Mayo Clinic Proc. 1992; 67: 1075-1079.

9. Turjanmaa K. Hand eczema from rubber gloves. In Mellstrom GA, Wahlberg JE, Marback HI, eds. Protective Gloves for Occupational Use. Boca Raton, Fla: CRC Press; 1994.

10. Fay M. The role of surgical gloves in hand dermatitis. Complications Surg. November 1991; 12-14, 44.

11. Hamann C, Kick S. Update: Immediate and delayed hypersensitivity to natural rubber latex. Cutis. November 1993; 52: 307-311.

12. Kokoszka J, Nelson R. Latex anaphylaxis. Dis Colon Rectum. September 1993; 36(9): 868-872.

13. Fritsch D, Frederick D. Exposing latex. Nursing. August 1993; 46-48.

14. Lahti A, Turjanmaa K. Prick and use tests with 6 glove brands in patients with immediate allergy to rubber proteins. Contact Dermatitis. 1992; 26: 259-262.

15. Yunginger JW, Jones RT, Fransway AF, et al. Extractable latex allergens and proteins in disposable medical gloves and other rubber products. J Allergy Clin Immunol. 1994; 93: 834-842.

16. White N. Understanding latex. Biomed Instrum Technol. June 1992; 232-237.

17. Sherman S. Precautions reduce risk of latex reactions. OR Manager. August 1993; 9(8): 17-20.

18. Korniewicz DM, Laughon BE, Butz A, Larson E. Integrity of vinyl and latex procedure gloves. Nurs Res. May/June 1989; 38(3): 144-146.

RELATED ARTICLE: Harvesting Hevea brasiliensis

Natural rubber latex is a product of the rubber tree Hevea brasiliensis, which originated in the Amazon. Most of today's rubber tree plantations are located in Malaysia, Indonesia, and Thailand, however.

Rubber trees must grow from 6 to 8 years before they are ready to harvest but then can produce latex for up to 28 years. One tree will produce approximately 10 pairs of surgical gloves each week.[1] The milky sap (latex) contains about 30% rubber, 65% water, 1.8% protein, and 2% resin. Rubber particles are coated with phospholipids and protein to help provide stability and prevent the latex from coagulating.[2]

If steps are not taken to stabilize the natural rubber, it spontaneously coagulates within the first few hours after collection due to microbial attack on the nonrubber constituents and the hydrolysis of protein.[2] The most widely used, method of preserving latex is adding ammonia, which helps prevent microbial attachment.

During manufacturing, many chemicals are added to the latex, including vulcanizers, accelerators, stabilizers, and antioxidants.[2] The exact mixture and process varies, depending on the physical properties needed for the application of the rubber. Each formulation of latex is designed to produce a product with the appropriate tensile strength and, if needed, barrier protection.

References

1. Hamann C. Natural rubber latex protein sensitivity in review. Am J Contact Dermatitis. March 1993; 4(1): 4-21.

2. White N. Understanding latex. Biomed Instrum Technol. June 1992; 232-237.

Christine D. Personius, MT(ASCP), CLS(NCA) is a medical technologist at Robert Packer Hospital in Sayre, Pa. Before that she was research technician on a project investigating latex allergies, conducted at the Donald Guthrie Medical Research Foundation, also in Sayre. She thanks Carol Camp, Terrie Zimmer, and Donald Beezhold for their time and effort in reviewing this article.