As a measure of infection control, all health professionals are urged to observe universal precautions. During the last fifteen years, an increasing number of dental professionals has started using gloves during all dental procedures to reduce the risk of disease transmission. The use of latex gloves has resulted in sensitization to latex of patients and practitioners. Allergic reactions to natural products items used in health care settings have become of increasing concern.
Epidemiology
In July 1991 the U.S. Food and Drug Administration issued a medical alert on allergic reactions to latex-containing medical devices, and requested that all physicians report patients who demonstrated allergic reactions to latex.
An international conference, "Sensitivity to Latex in Medical Devices," was held in Baltimore in Nov. 1992 to discuss the etiology, clinical evaluations, product development and research on reactions to latex, and to educate technologist, radiologist and nurses about latex allergy. The American Academy of Allergy and Immunology formed a special committee to study the proposed FDA guidelines and other issues related to latex protein allergy. In 1992, Midmarc, which insures about 14% of medical product manufacturers asked its clients to begin labeling all products containing latex or natural rubber.
The efforts to monitor the latex allergic reactions among patients and practitioners produced results. The U.S. Food and Drug Administration received 1,118 reported cases of reactions to latex in a four-year period. There were 19 cases involving rubber dams, 407 involving examination gloves (both patients and health care workers reporting reactions to latex); and 77 reports involving surgeons' gloves, mostly involving patients. In addition, there were many published accounts of reactions to rubber dams and gloves used in dental procedures.
The FDA estimates that about 6 to 7% of medical personnel may be allergic to latex. There is evidence that dental professionals may be more allergic to latex than the general population. A survey of periodontists, hygienists, and dental assistants found that 42 percent reported adverse reactions to occupational materials, most of which were related to dermatoses of the hands and fingers. Atopic individuals reported the most severe reactions.
Atopy is an inherited tendency to develop some type of allergy, including several forms of allergies such as hay fever, eczema, and asthma. Individuals with spinal cord deformities, including spina bifida, also have an extremely high incidence of latex protein allergy, ranging from 18 to 40 percent. It is suggested that health care professionals should consider all spina bifida patients inherently allergic to natural rubber.
Introduction of Protein Allergens During Manufacture
The history of allergy to latex products in humans goes back several decades. As early as 1913 there were reports of rubber glove dermatitis among public utilities linemen. Some common symptoms were itching, subsequent swelling and vesiculation on the hands, all of which are common to urticaria.
Over the years there has been a steady increase in the number of cases of hand dermatoses resulting from the use of rubber gloves, from six cases in 1949 to 40 cases in 1954. According to one theory about latex allergy, latex gloves inhibit epidermal cell proliferation and cause pronounced complement activation in vitro. In gloved hands, small skin lesions have little chance of healing and skin becomes sensitized to latex allergens.
The raw ingredient of natural rubber products is latex, a white milky sap extracted from tropical trees. Latex sap contains spherules of rubber, which are associated with a small amount of protein. Most natural rubber proteins, however, are found in a hydrophilic portion of the sap called serum.
Ammonia is the preservative added to the sap which hydrolyzes the sap proteins, changing and degrading them. The end result is numerous protein allergens making it difficult to identify the specific proteins that cause the allergic reaction. This is why to this date there is no standardized test for latex allergy.
The next step in the making of natural rubber products is centrifuging the latex sap and collecting the rubber spherules. Centrifugation removes many impurities but not all serum proteins which may induce allergic reaction in many individuals are removed during this step.
There is yet another step that introduces allergens to rubber products such as gloves. Chemicals used in the manufacture of dipped products, such as gloves and condoms, may be responsible for cell-mediated or delayed Type IV allergy. Type IV allergic reactions range from simple irritations and contact dermatitis and, usually, occur 24 to 48 hours after exposure and affect only the exposed area.
Liquid latex undergoes vulcanization process during which it is subjected to sulfur and heat, turning the liquid mass into hardened rubber. The final manufacturing step calls for leaching of rubber products. During leaching, products are soaked in hot water to finalize curing. To reduce the possibility of latex antigens or processing chemicals seeping into final products in increasing concentrations, leaching water is replaced constantly during the curing process.
Proteins migrate toward heat during leaching. In dipped products produced on molds, as is the case with rubber gloves, leaching can bring allergens to the surface. The gloves are removed from the mold inside out which means that the wearer's skin will come in contact with the highest concentrations of allergens. The surface proteins can be removed with exhaustive washing, but that may make them unusable. The gloves are removed from the mold using cornstarch powder which may also be contaminated with latex protein allergens. The attempt to remove the powder by exhaustive washing creates the same problem of creating microholes in the gloves, rendering them unusable.
Allergy Development
The following factors contribute to allergy development:
a) Repeated exposure to an antigen increases sensitivities to that agent. This is why medical and surgical personnel and individuals undergoing surgery have a high incidence of latex allergy.
b) Duration of exposure Surgeons and health care workers who wear gloves for extended periods of time are more prone to allergic reactions.
c) Moist skin Latex antigens are water soluble making individuals with moist skin more susceptible to allergic reaction.
d) Hand lotions and creams also increase the amount of protein that transfers from the glove to the wearer.
e) Cornstarch has been linked to latex allergy in some research. Most gloves are powdered with cornstarch which can adsorb allergens from the latex. These adsorbed antigens could sensitize patients to latex during surgery if these particles contaminate wounds. Powders unadulterated with latex antigens have not been shown to cause allergic responses.
Diagnosing Allergies
Allergies are difficult to diagnose because reactions vary from simple irritations to mild allergic reactions (such as wheezing, localized rashes or swellings) to anaphylactic reactions. These reactions vary from one individual to another and often produce different reactions in the same individual under seemingly similar circumstances.
Those most likely to have reactions are patients with spina bifida, persons who have undergone repeated surgery that involved extensive contact with rubber tubes or post-surgical drains and other rubber products, and patients with a history of other types of allergy.
The variations in allergic reactions can be attributed to the variation in the quality and quantity of protein in latex products. Adding to the variability is the property of latex proteins to attach themselves to powders used in gloves, allowing them to be airborne causing reactions without actual physical contact.
Latex proteins may be solubilized, attached to the cornstarch powder lubricant of gloves or found in an insoluble state.
All of the above factors contribute to the great variability in reactions to allergens found in latex products.
Allergic Reactions
Patient allergic reactions to latex encountered in dentistry vary in type and intensity. Many health care workers who are allergic to latex first notice erythema, rashes, pruritis or similar problems with their hands. These are symptoms of allergy, either delayed or immediate. Delayed reaction allergies initiate small breeches in the skin. This allows latex to enter the bloodstream, resulting in an immunoglobulin E allergy.
The common approach to dealing with such problems is to 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 while immunological symptoms escalate, as the individual continues to ignore them.
This can worsen the allergy culminating in anaphylaxis when the individual undergoes some type of surgical procedure.
Anaphylactic reaction is an immediate hypersensitivity response, commonly known as Type I immunologic reaction. Other Type I reactions are penicillin allergy, bee sting reactions, extrinsic asthma and allergic rhinitis.
Atopic individuals typically experience Type I chronic allergic reactions such as hay fever and eczema. Acute Type I reactions, such as asthma, uticaria and systemic shock are considered anaphylactic responses.
These reactions are mediated by IgE antibodies and progress in two phases: rapid and slow reactions. IgE antibodies can be found on mast cells in the tissues or basophils in the blood. When the latex antigen and an antibody attached to the mast cell or basophil react with each other, the cell rapidly releases its granules. These granules contain histamine, heparin, seratonins and arachidonic acid.
Common symptoms of the rapid phase of an anaphylactic reaction include:
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constriction of smooth muscles that have H1 receptors, including bronchi- oles, leading to asthmatic reaction; gastrointestinal tract, producing diarrhea and vomiting; genitourinary, causing involuntary urination; endothelial cells, inducing edema; |
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dilation of smooth muscles lining arterioles, which have H2 receptors, precipitating a drop in blood pressure leading to shock. |
The slow phase begins six to 12 hours after exposure to the allergen, leading to painful erythematous induration of the skin and prolonged bronchoconstriction, as well as increased gastric, respiratory and lacrimal secretions.
The rapidity, severity and scope of an allergic reaction are probably dependent on the route of exposure. A surgical procedure introducing antigens directly into the bloodstream is much more likely to cause acute anaphylaxis than a procedure where skin barrier is broken. In the latter case, the patient may suffer from angioedema or wheal and flare (hives) reaction. This may be the only clue that the patient could be allergic to latex proteins.
According to the FDA, mucous membranes may be especially reactive in the latex sensitive patient, so the dental health care worker should be cognizant of the possibilities of allergic reaction.
Precautions Against Latex Reactions
Latex reactions are a source of concern in the delivery of health care. Three American Dental Association councils have issued a report with recommendations for minimizing adverse reactions to latex in the dental office. By including questions about latex allergy in the patient medical history and using alternative materials where indicated, dentists may prevent many allergic reactions to latex.
In patients, adverse reactions to latex may range from simple irritations or mild allergic reactions (e.g., wheezing, rash) to anaphylaxis. Latex sensitivity is more common in patients with spina bifida, those who have undergone repeated surgery involving extended contact with latex products, and patients with other types of allergy.
When taking the medical history, the dentist should inquire about the presence of any allergic reaction following contact with latex gloves or balloons. When a positive history is elicited, staff should use gloves made of vinyl or other synthetic polymers in place of latex; non-latex dental dams may be made of synthetic polymer glove material. Dentists may recommend that the patient undergo immunologic evaluation or wear a medical alert bracelet.
Among dental health care workers, the latex reactions that may occur include irritations, contact dermatitis, and anaphylaxis. Increased exposure to latex may heighten the risk and severity of reactions. Gloves should be worn only when needed for infection control purposes or to protect hands from chemicals or contaminated instruments. When changing gloves, hands should be allowed to dry completely before putting on gloves, and use of a skin lotion may help prevent irritation. Contact dermatitis should be treated promptly, with the affected worker limiting latex exposure during treatment.
To prevent anaphylactic reactions in latex-sensitive patients, clinicians may use synthetic gloves. Such gloves, however, may be vulnerable to solvents used in denstistry. For alternatives to latex gloves and other devices, see Table 1.
| Latex Product | Substitute |
| Rubber bite blocks |
Molt mouth prop: Remove latex sleeve, wrap with gauze |
| Rubber dam | Synthetic glove |
| Orthodontic elastics | Closing springs |
| Prophylaxis cups | Prophylaxis brushes |
| Blood pressure cuff | Plastic disposable cuff; or contact area may be covered |
| Anesthetic cartridges | Anesthetic drawn from ampules or vials |
| Penrose drain |
Drain made with synthetic glove |
Although immediate hypersensitivity to rubber is relatively common among patients with regular exposure to the material, severe anaphylactic reactions are unusual. One such reaction, possibly from sensitization to latex rubber gloves during numerous operations and vaginal examinations, is reported below:
Case Report Woman, 31, experienced facial and eyelid swelling, throat tightness, and shortness of breath with wheezing 10 minutes after leaving a hospital consultation. During the consultation, the patient's gynecologist had conducted a vaginal examination while wearing a rubber glove. Her general practitioner arrived and found the patient moribund. Anaphylaxis was diagnosed, and the woman was given adrenaline, chlorpheniramine, and hydrocortisone. The patient went into respiratory arrest during transfer to the hospital but survived. Her medical history included delayed hypersensitity to nickel and multiple operations. The patient also reported a previous and less severe episode of facial swelling and wheezing after blowing up some balloons for a party.
Immediate hypersensitity to latex rubber was believed to have caused the anaphylactic episode. The patient experienced a complete recovery and was discharged 24 hours after the incident. She was given syringes preloaded with adrenaline (0.5 ml 1/1000) for intramuscular injection and 240 mg oral terfenadine to use at the onset of another attack.
Blood tests done 36 hours after the reaction showed normal C3 and C4 concentration of 0.12 g/l, which ruled out angioedema. A prick test using a 1-cm-square piece of latex rubber revealed a positive hypersensitivity reaction 10 minutes later. No such reaction was noted when a control polythene glove was used. Prick testing with natural rubber latex showed a 5-mm wheal and 15-mm flare; no reactions were seen in six control individuals. Parch tests with various other rubber chemical were negative.
Four months after the initial reaction, the patient experienced another attack of wheezing and shortness of breath after the flow of air from a deflating rubber cushion was directed at her face. During the episode, she injected the adrenaline given to her for home use. The reaction was less severe than the initial event, but hospital admission was still necessary.
Case Histories Related to Latex Glove Allergy
Latex gloves worn during dental treatment can lead to adverse patient reactions, ranging from contact urticaria to systemic anaphylaxis. Patients experiencing adverse effects after contact with latex gloves or chemicals involved in the manufacture of latex are reported, as are measures that can help reduce the occurrence of allergic or anaphylactic reactions.
Those most likely to have reactions are patients with spina bifida, persons who have undergone repeated surgery that involved extensive contact with rubber tubes or post-surgical drains and other rubber products, and patients with a history of other types of allergy.
Case 1 The first patient, a 76-year-old woman, noted a red area on the left side of the neck after preliminary impressions were obtained prior to provision of a maxillary partial denture. On examination, erythematous areas on the left side of the neck extending from the angle of the mandible toward the chin were noted. A smaller, bilateral erythematous area also was observed at the angle of the mouth. The inflammation subsided within 24 hours. The affected areas corresponded to the area likely to be in contact with a gloved hand during treatment. An allergy to latex was therefore suspected and confirmed by patch testing. The patient was effectively managed during later visits by an operator wearing vinyl gloves.
Case 2 The second patient, a 42-year-old woman, was noted to have increasing swelling to the left side of her lip during maxillary left first molar restoration, which was not associated with the injection site or treatment-related trauma. Over the course of an hour, the swelling spread across the midline, although no increase in size was noted thereafter. The swelling subsided after 6 hours, and the lip returned to normal size 24 hours later. The patient had reported slight swelling to the lip during previous dental treatment. Latex-allergy-related angioedema was suspected, and tests for allergy to local anesthesia solution and latex verified the diagnosis. The patient's history was significant for allergies to various foodstuffs, as well as aspirin, hay fever, asthma, and eczema. Vinyl gloves were worn during subsequent treatment.
Case 3 The third patient was a 60-year-old man who experienced circumoral erythema after undergoing general dental treatment. The patient was then referred to the dental hospital for further management, at which time he reported having previously noted a reddening of the scalp after wearing a rubber swimming cap, as well as multiple allergies. Patch testing was performed, and results indicated allergy to various chemicals used during latex glove production. Treatment was successfully carried out by an operator wearing polyvinyl overgloves.
Conclusions Patients can experience adverse reactions after contact with latex gloves worn during dental treatment. Many patients who have latex hypersensitivities also have a history of other allergic conditions, such as hay fever. Allergy history should be obtained before undertaking treatment. Patients also should be questioned about any symptoms experienced after contact with latex-containing objects and any allergic or anaphylactic reaction that may have occurred after a medical procedure. When allergy is suspected, additional testing is necessary. Vinyl gloves or polyvinyl overgloves may be used for individuals with an identified latex allergy.
Treatment Immediate diagnosis and treatment of severe systemic anaphylaxis is needed to prevent death. The differential diagnosis includes vasovagal reaction, asthma, myocardial infarction, dysrhythmia, anxiety-related fainting, and effect of sedatives or local anesthetics. If a patient with anaphylaxis is unconscious, cardiopulmonary resuscitation should begin. For rapid-onset reactions, epinephrine should be given; if the practitioner cannot administer it intravenously, an intramuscular injection may be given with EpiPen, EpiPen Jr., Ana-Guard Epinephrine, or Ana-Kit. The deltoid is the recommended site of injection. If the primary symptoms are delayed-onset hives and itching, intramuscular injection of antihistamines is needed.
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REFERENCES
1. Burke FJT, Wilson MA, McCord JF: Allergy to latex gloves in clinical practice: Case reports. Quintessence 26;859-863, 1995.
2. Council on dental materials, instruments and equipments; Council on dental therapeutics; Council on dental research. JADA, Vol. 124, Dec. 1993.
3. Dealing with patient/worker concerns. J Am Dent Assoc 124(12): 91-92, 1993.
4. Mansell P, Reckless JPD, Lovell CR: Severe anaphylactic reaction to latex rubber surgical gloves. BR Dent J 178:86-87, 1994.
5. Snyder HA, Settle, S: The rise in latex allergy: Implications for the dentist. JADA, Vol. 125, Aug. 1994.