Latex Allergy: Everyone's Concern


By Lawrence D. Duffield, DDS
Journal of the Michigan Dental Association
June 1998

A patient comes into your dental office, a bead of sweat on his forehead. As he nervously inspects his surroundings, his heartbeat quickens. He feels his life could be at stake; his hands are locked to the arms of his chair in a death grip. The dentist, hygienist, and assistant, too, are nervous. The receptionist is poised to speed-dial 911.

Why?

The patient is latex-sensitive. Although no deaths have occurred in a dental setting due to latex allergy, clinicians should maintain a high index of suspicion to prevent a catastrophic reaction..(1) According to FDA Medwatch data as far back as June 1996, there were 28 reported deaths and 225 anaphylactic events associated with latex products in all settings.

Recent reports in the literature indicate that from about 1 percent to 6 percent of the general population and about 8 percent to 12 percent of regularly exposed health care workers are sensitized to latex (Kelley et al. 1996; Katelaris et al. 1996; Liss et al. 1997; Ownby et al. 1996; Sussman and Beezhold 1995). This means perhaps up to one million health care workers are at risk for latex reactions.

The chance of a latex-sensitive person coming through your door escalates every day. All health care professionals need to know about this potential hazard and be able to manage it effectively if encountered.(2) Often, an individual may not be aware that it is latex that causes his or her sensitivity. A simple question, such as, "Are you allergic to latex?" may not suffice. The patient should be asked follow-up questions such as:
  • "Have you experienced hives, wheezing, rashes, coughing, or difficulty in breathing when handling items like balloons and rubber balls?"
  • "Have you experienced any of these symptoms after contact with medical or dental products like rubber gloves or dental dams?"
  • "Have you ever worked in a health care setting? In the rubber industry?"
  • "Have you ever had surgery? How many times? Did you ever experience any complications during surgery that required resuscitation?"
Why is this problem growing?
There are many theories that attempt to explain the increasing prevalence of latex (also known as natural rubber latex) allergies. The main theory states that the cause is increased exposure to latex gloves, due to the increased demand for personal protection in response to the AIDS crisis. Other theories include changes in concentration and/or allergenicity of the proteins contained within the latex products. Increased demand for latex gloves has created changes in glove processing and manufacturing. These changes include shorter wash and shelf times, which have increased the amount of latex protein antigens in gloves and other products. Despite improvements to the manufacturing process, high levels of extractable latex antigens are still being found in latex gloves.

Latex is a complex product of the Brazilian rubber tree Hevea brasiliensis, which is predominantly cultivated for commercial use in the Pacific Rim countries. A milky fluid is tapped from the tree, in much the same way as is done with maple sap. The raw product is then mixed with preservatives, accelerators, and various other chemicals. Although synthetic polymers (i.e. polyvinyl chloride, nitrile, silicone) have replaced many natural rubber latex products, it is latex's elasticity, durability and cost-effectiveness that have made it the material of choice for many products.

It is estimated there are approximately 40,000 different products that contain natural rubber latex that are used every day by millions of Americans. These products include tennis shoes, balloons, condoms, tires, chewing gum, the scratch-off portion of the instant lottery ticket, catheters, anesthesia devices and protective gloves. Although latex products play an important part in providing effective barrier-protection for millions of health care workers, they are not appropriate for everyone.

Types of latex reactions
Irritant Contact Dermatitis. This is the most common reaction to latex products--the development of dry, itchy, irritated areas on the skin. This reaction results from repeated hand washing and drying, incomplete hand drying, use of cleaners and sanitizers, and exposure to powders added to the gloves. Irritant contact dermatitis is not a true allergy.(3)

Type IV (Delayed) Hypersensitivity. Allergic Contact (Chemical Sensitivity) Dermatitis results from exposure to chemicals added to latex during harvesting, processing or manufacturing. Latex glove products utilize coagulants, accelerators, antioxidants, emulsifiers, stabilizers, extenders, colorants, stiffeners, biocides, fragrances, etc.(4) These chemicals can cause skin reactions similar to those caused by poison ivy. As with poison ivy, the rash usually begins 24 to 48 hours after contact, and may progress to oozing skin blisters or may spread away from the area of skin touched by the latex. This contact urticaria may represent a transitional stage in a progression between contact dermatitis and immediate hypersensitivity. Some patients initially develop delayed-type contact dermatitis, then urticaria, and finally (months to years later) systemic immediate hypersensitivity.(5)

Type I (Immediate) Hypersensitivity. This is an IgE antibody mediated reaction to some of the protein antigen inherent in the latex. These reactions typically cause urticaria, angioedema, rhinitis, conjunctivitis, bronchospasm, asthma and, rarely, anaphylaxis. Affected persons must eliminate latex exposure altogether.(6) Although the amount of exposure needed to cause sensitization or symptoms is not known, exposures at even very low levels can trigger allergic reactions in some sensitized individuals. A common factor in anaphylactic episodes is exposure of mucosal tissues to latex--a situation inherent in dentistry.(7) The potential for a life-threatening anaphylactic reaction underscores the importance of recognizing Type I immediate reactions.

Table One: REACTIONS TO NATURAL RUBBER LATEX

Reaction Type Irritation Delayed Type Hypersensitivity Immediate Sensitivity
Also Known As: Irritant contact dermatitis Type IV hypersensitivity Allergic contactdermatitis
Cell mediated allergy
Chemical allergy
Type I hypersensitivity IgE mediated allergy Latex protein allergy
Cause: Hyperhydration
Maceration
Excessive occlusion
Insufficient handrinsing
Chemical contact
Sensitizers: usually accelerators
Protein allergens from natural rubberlatex
Immediate Intervention N/A N/A Emergency treatment for anaphylaxis maybe required
% of Population Prevalence 100% 7-18% General population: <1% Health care pop.: 3-12%
Time To Onset Of Symptoms Minutes to hours 6 to 48 hours Minutes to 1 hour
Potential for Respiratory Involvement No No Runny nose, wheezing,difficulty breathing
Facial Involvement If face is touched If face is touched Swelling of eyelids,lips, face; tearing,itchy eyes, runnynose
Systematic Involvement No No Hives, nausea, abdominal cramps, rapid heart rate, lowblood pressure, anaphylaxis
Potentially Life Threatening? No No Yes
Action Wash and rinse hands thoroughly. "hypoallergenic"gloves are processed See an allergist,wear an alert
See dermatologist ifsevere. to be low in chemical sensitizers. bracelet, carry an EPI-Pen, alert fellow employees

Who is at Risk?
Children with spina bifida are at extraordinary high risk of latex hypersensitivity. It is believed that this is due to extensive latex exposure in early life.(8) Patients with congenital urogenital anomalies and spinal cord injuries are considered high-risk. Health care workers who have frequent and prolonged occupational exposure to latex also have an increased risk of developing severe latex allergy.(9) Workers in factories where latex products are manufactured or used can also be affected. Atopic individuals (persons with a tendency to have multiple allergic conditions) are at increased risk for developing latex allergy. Workers who use latex gloves less frequently (law enforcement personnel, ambulance attendants, funeral home workers, fire fighters, painters, gardeners, food service workers, and housekeeping personnel) may also develop latex allergy.

Latex allergens and diagnosis
Type IV Latex Allergy (cell mediated), also known as Allergic Contact Dermatitis Delayed Hypersensitivity, typically is a reaction to excess residual chemicals used as accelerators and antioxidants in the manufacturing process.(10) Ironically, the term "hypoallergenic" originates from this type of sensitivity. Before it was realized that there was a true latex allergy, it was believed that the allergic response was due to the chemicals used in the processing of latex gloves. Therefore, gloves that were lower in content of these sensitizing chemicals could bear the label "hypoallergenic". But the emergence of latex protein allergy has rendered this simple labeling process obsolete and misleading.(11) The FDA has issued a regulation eliminating this inaccurate label.

Type I Latex Allergy (IgE-mediated), also known as Natural Rubber Latex Proteins Type I Immediate Hypersensitivity, develops in response to water-soluble proteins that remain in the latex following the manufacturing process. With more than 200 proteins, definite testing for latex allergy is inconsistent and difficult. Over 50 of these proteins have been shown to have allergenic potential.

Diagnosis of (Type IV) Contact Dermatitis. Contact dermatitis makes up the majority of occupational skin diseases. Patch testing with an array of commercially available allergens is the accepted method for identifying a delayed reaction to rubber processing chemicals. The patch test is typically conducted by a qualified clinician using a standard series of patch test allergens on the upper back. The patches are typically removed and the test sites examined at 48, 72, and 96 hours. If positive, the patient should be provided with information regarding the offending chemical and prevention of a type IV allergy.

Diagnosis of (Type I) Latex Allergy. Diagnosis of latex allergy is based on a history of latex exposure and reactions, physical signs of latex hypersensitivity, and a positive blood test (RAST) or skin test for IgE antibodies to latex allergens. Testing for immediate hypersensitivity to latex is particularly difficult for most physicians because of a lack of standardized, FDA-approved testing materials.(12) Some physicians make up their own "latex serum" for skin testing.

Unfortunately, even skin testing can provoke anaphylactic reactions.(13) Occasionally, tests may fail to confirm a worker who has a true allergy to latex, or tests may suggest latex allergy in a worker with no clinical symptoms. Therefore, test results must be evaluated by a knowledgeable physician.

Failure to properly diagnose latex hypersensitivity may result in unnecessary exposure to latex and serious allergic reactions. If patient is found to have a Type I allergy all contact with latex must be avoided.

How to Treat the Latex-Allergic Patient
Due to the increasing frequency of latex allergy and its possible dire consequences, all dental patients should be screened for an allergic condition. The risk for spina bifida patients is so high that many medical institutions treat these patients routinely in a latex-free environment.

Treating the allergic patient requires identifying which type of hypersensitivity your patient exhibits. If you are not sure, it is best to first have the patient seek a diagnosis from an experienced dermatologist or allergist. A clear diagnosis can help dental workers choose alternative nonallergenic products to reduce their own exposure, or to treat their patients without the risk of complications. Management involves identifying the problem and completely avoiding allergen exposure. However, latex is used in thousands of products, and avoidance of antigen sources is not always a simple matter. Suitable latex-free replacements do exist for most items, but not all.

Charts of patients known or suspected of having an allergy should be prominently flagged. Emergency resuscitative medication, such as epinephrine, should be available in case a patient experiences an anaphylactic reaction despite all precautions. Staff should be trained and ready to assist during such an emergency.

There are two main sources of latex exposure to our patients. The primary source is latex gloves. The practitioner must wear nonlatex gloves for the latex-sensitive patient. The second source is aerosolized latex. Latex proteins adhere to the cornstarch powder added by manufacturers to assist in donning and removal. It is a common misconception that it is the powder to which a person is allergic; rather, it is the protein sticking to the powder.

Each time powdered gloves are used, latex is introduced into the air, where it can remain up to 12 hours.(14) This "latex dust" acts as a sensitizing aeroallergen, and in sensitive people has caused serious, asthmatic life-threatening reactions. Therefore, merely wearing nonlatex gloves while treating an allergic patient may be an inadequate precaution when powdered latex gloves are being used elsewhere in the office.

If there is any question of safety, it is often advisable to have an allergic patient come to your office and simply sit in your waiting room. If there is any risk, it may be prudent to refer the patient to a latex-safe office.

For the latex-allergic patient, the following are recommended:
  • The patient should be the first patient of the day (low "latex dust");
  • no direct contact with latex is allowed;
  • nonlatex substitutes for patient care must be used: prophy cups, dental dam, N20 mask, etc.;
  • latex in the room must be ALARA (As Low As Reasonably Achievable);
  • any latex items that cannot be removed must be covered;
  • the room should be close to the entrance (in case of emergency);
  • personnel setting up the room must wear nonlatex gloves;
  • instruments must be handled only with nonlatex gloves;
  • lab work must be handled with nonlatex gloves and thoroughly rinsed before placement;
  • multi-dose glass vials of anesthetic or glass ampules should be used;
  • if the patient is taking beta blockers, a medical consult must be done (these drugs interfere with the medications needed to resuscitate a patient should an emergency arise);
  • use nonlatex blood pressure cuffs;
  • wear minimal perfume and aftershave;
  • gutta percha has a potential for cross-allergencity (an alternative is Ketac-Endo fill).
Table Two: Consumer Products that Often Contain Latex

Household gloves
Rubber balls
Balloons
Condoms
Diaphragms
Carpet backing and pads
Foam rubber
Bath mats
Elastic clothing and disposable diapers
Infant pacifiers and bottle nipples
Rubber toys
Rubber bands
Automobile tires
Swimming, snorkeling and scuba equipment
Athletic shoes
Crutches (arm and hand pads)
Rubber boats
Rubber cement
Sports racquet handles
Pencil erasers
Halloween masks


Treating the Latex-allergic Dental Worker
The incidence of latex allergy among dental personnel may be higher than the average health care worker because dental personnel wear latex gloves most of the working day. Recent findings suggest that latex sensitivity is becoming a serious occupational hazard among the dental community.(15) Latex sensitivity is a complex issue, and if a worker has a severe reaction sometimes he or she is never able to return to his or her work environment.(16) Actions taken to increase employee protection against bloodborne pathogens have inadvertently also lead to increased glove-related dermatological reactions.(17)

"Latex is the allergen of the '90s," says Kevin J. Kelly, M.D., director of pediatric allergy and immunology at Children's Hospital of Wisconsin in Milwaukee. "We simply can't afford to sensitize and potentially lose a large segment of our highly trained well-paid health care professionals. I've seen physicians, surgeons, nurses, laboratory technicians, and researchers develop such severe occupational asthma that they become totally disabled professionally."(18)

If you or a fellow worker develop symptoms of latex allergy (including, but not limited to: hives, itching, swelling, watering eyes, nasal congestion, sneezing, coughing, wheezing, or asthma), do not ignore the problem! It's important to catch the problem early, before more serious symptoms develop.(19) Evaluation by an allergist well-informed about latex allergy is essential.

The common approach to dealing with such problems is to either ignore them, endure them or use steroid creams to alleviate the symptoms. Unfortunately, this allows the body to build even greater levels of antibodies to latex proteins. Years may pass, and immunological symptoms escalate, as the individual continues to ignore them. This can worsen the allergy.(20) Some individuals, who have used gloves uneventfully for years, may experience a rapid "march" of symptoms commencing with contact dermatitis and progressing to systemic reactions.(21) The development of a Type I sensitization is asymptomatic until a threshold level of sensitized mast cells is reached.(22)

When sensitized health care workers continue to be exposed to latex, asthma may develop. This may progress and persist even after strict avoidance of the workplace and other sources of latex. Pulmonary function may remain permanently impaired even after leaving the health care profession.(23)

If you are diagnosed with Type I allergy, you should avoid all contact with latex. Carry an Epi-Pen. Wear an alert bracelet or necklace. Alert fellow employees and/or your employer. Working in an area where coworkers are still using powdered latex gloves is dangerous. All offices with a sensitized employee must use low-allergen, power-free gloves. If symptoms persist, do not ignore them. It is imperative that continual sensitization is halted.

Table Three: Items Used In Dentistry that May Contain Latex

Anesthetic carpule (latex stopperand diaphragm)
Bite block
Blood pressure cuff
Endodontic stops
Gloves
Gutta percha
Hoses (saliva ejector and HVE)
Instrument bands
Mixing bowls
Nitrous oxide masks and hoses
Orthodontic bands and elastics
Polishing wheels and points
Prophy cups
Rubber dams
Stethoscope
Toys, prizes, stickers, balloons
Widgets


Hand Care
Proper hand care is essential for reducing the possible deleterious effects of glove use. Irritation is most often caused by chemicals that are not related to gloves. Common irritating substances include soaps, detergents, and disinfectants, especially when they are left on the skin after insufficient rinsing. Gloves may enhance the effects of these irritants, as they provide a warm, moist, occlusive environment encouraging dermal penetration of irritants. Jewelry unnecessarily increases the potential for irritation by inhibiting proper rinsing.(24)

Gloves should be removed frequently to prevent hyperhydration of the epidermis and to limit the adverse effects of excessive occlusion. When hands sweat inside gloves, more protein is dissolved with the powder, and more reaction can occur. Relief of irritated hands is sometimes found by donning gloves larger than those normally chosen, thereby increasing air circulation and reducing friction.

A long-term hand care regimen is necessary in order for personnel to maintain healthy skin. Such a program should incorporate washing with a mild soap, thorough rinsing, and using a lotion, especially in off-duty hours. As the body's first line of defense, it is imperative that epidermal integrity be preserved. Ideally, hand irritation should be healed before returning to work. If not, a synthetic alternative glove may be chosen to reduce the risk of self-sensitization. Hands should always be bone-dry before placing gloves on.

Individuals often use mineral oil, lanolin, cocoa butter, jojoba oil or petroleum lotions or salves to moisten and heal skin. But these agents act as plasticizers, disrupting the chemical bonds that maintain material strength of latex and many synthetic glove materials.(25 26) Although a hand care regimen incorporating these ingredients is encouraged away from work, only latex-compatible, non-oil based lotions can be used when wearing gloves.

Glove Selection
Proper glove selection is critical in providing our patients with a safe environment and in minimizing our own workplace self-sensitization. The exact level of latex protein exposure required to induce sensitization is not known. However, it is clear that significant exposure to latex gloves is the most common source of sensitizing allergen. The abrupt increase in sensitization may be associated with the increased glove usage mandated by universal precautions, but changes in manufacturing, latex processing and sources of latex may also have contributed significantly to the problem.(27)

The amount of latex allergen in the air where powdered latex gloves are used regularly is considerable.(28) Changing to powder-free gloves reduces the airborne allergen load to undetectable levels.(29) The American College of Allergy, Asthma and Immunology has issued guidelines recommending that nonpowdered, low-protein gloves be the standard in health care facilities, and that powdered, low protein gloves be available only on request and their use monitored. The college also advised that latex-sensitized workers wear only synthetic gloves, and that their co-workers wear powder-free low-protein gloves.

Dental professionals without latex sensitivity should voluntarily switch to low-allergen, powder-free latex gloves. For those with latex sensitivity, a synthetic glove is essential. Determining which gloves are low-allergen may be difficult, because there is no standardized test to determine allergen levels. Researchers still are looking for the best way to measure the latex proteins, antigens and allergens in gloves, to try to understand their significance. They have not yet identified all the specific proteins that cause allergic reactions; therefore they do not know which proteins are the correct ones to measure. Also, because sensitivity differs from person to person, it is difficult to know what type of allergen, and how much of it, is needed to trigger a reaction.(30)

In procuring low-allergen latex gloves, you can request from the manufacturer test documentation of glove protein levels. Although these values may differ from one test group to the next, the relative order of the latex gloves is usually the same. Make sure test data is up-to-date. Data collected two years ago may have little relation to gloves being produced today.(31) Most of the major manufacturers are rapidly changing in order to reduce allergen content.

There can be a 3,000-fold difference in allergenicity among different glove brands. Wearing one high-allergen glove can be tantamount to wearing 3,000 low-allergen gloves! Gone are the days when you could simply buy the cheapest pair of latex gloves on the market and feel safe.

Latex sensitivity could be greatly reduced by choosing powder-free, low-allergen latex gloves. Due to chlorination (which assists the donning process), powder-free exam and surgical gloves contain significantly lower amounts of allergens than powdered gloves. The market is expected to shift toward powder-free and synthetic products.(32)

Where do we go from here?
It is important that health care workers be informed about the latex sensitivity issue. Latex is a puzzling material. On the one hand, it can be a fatal material for thousands of people. Yet latex gloves remain the most cost-effective and safest infection control barrier.(33) But latex is a potentially dangerous substance that must be used carefully.

The Mayo Clinic in Rochester, Minn., Henry Ford Hospital in Detroit, and many other hospitals have switched to low-allergen, powder-free latex gloves. In 1993, Shriners Hospital in Springfield, Mass., became one of the first hospitals in the nation to go "latex safe" (the term used instead of "latex-free," since it is virtually impossible to eliminate all latex products).

Legislation is pending in Minnesota, Oregon, New York, and Wisconsin to prohibit the use of powdered latex products by health care workers. The ADA Council on Scientific Affairs recently spoke out against state proposals to ban the use of powdered latex gloves.(34) The ADA reasoned that there is no scientific basis for such across-the-board prohibitions, and that much remains to be learned about latex sensitivity. While there may not be adequate reason for an outright ban, a prudent course of action would be a voluntary shift to powder-free gloves. This creates a safer work environment for our employees and our patients.

A new ruling by the Food and Drug Administration will require the following labeling statement on medical devices that contain natural rubber that contacts living human tissue: "This product contains natural rubber latex which may cause allergic reactions in sensitized individuals."

There are still many unanswered questions about latex. Assuredly, more people will die because of reactions to it. We in the dental profession can make a difference by reducing latex sensitization, educating ourselves and our patients, and doing no more harm. More research is needed in this area. The ultimate goal, of course, is an alternative to latex that is safer to use.

Dr. Duffield is a general practitioner in Royal Oak. He has a Type I latex allergy, practices in a latex-safe office, and lectures on latex allergies. He is a member of the MDA's Special Committee on Health and Hazard Regulations.

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Journal of the Michigan Dental Association
June 1998©
Michigan Dental Association
Reproduced here with permission.