__________________________________________________ DCA02AR Allergic Reactions in Dental Patients
Type I and type IV hypersensitivity reactions to opioid medi- cations are very rare [34]. More commonly, adverse effects of opioids (e.g., nausea, constipation, sedation, pruritus) may be erroneously considered allergic reactions. The chemical struc- tures of codeine, hydrocodone, and oxycodone are similar, and cross-reactivity is possible [35]. If a patient has a history of an allergic reaction to a combination medication, it is important to determine if the reaction was to the opioid, the non-opioid component, or both. If the source of the reaction cannot be determined, an alternative medication unrelated to any com- ponent of the combination medication should be prescribed. ALLERGIC REACTIONS TO MATERIALS USED IN DENTISTRY Various materials used in restorative and prosthetic dentistry can cause localized reactions of the oral tissues, as can ingredi- ents in commercial oral hygiene products, such as toothpaste and mouth rinses. Some materials, such as latex gloves, can cause a hypersensitivity reaction in clinicians and/or patients. NATURAL RUBBER LATEX All healthcare professionals use Standard Precautions to pre- vent the transmission of communicable diseases, including bloodborne pathogens. This includes the use of personal pro- tective equipment (e.g., masks, gowns, eye protection, gloves) during clinical procedures. Natural rubber latex gloves have been used extensively due to their high level of comfort and ability to maintain good dexter- ity and tactile sensation. Natural rubber latex is derived from the milky sap harvested from rubber trees. Accelerators and other chemicals are used to manufacture latex products, and a hypersensitivity reaction may be in response to any of these components. With approximately 4.5% of the general popula- tion and 10% of healthcare workers developing varying degrees of sensitization to latex, alternative materials such as latex-free nitrile gloves are beginning to be used more frequently [36]. However, many clinicians still prefer the use of latex gloves. Another possible source of natural rubber latex exposure is with rubber dams used in restorative dentistry and endodontics to provide isolation and to prevent salivary contamination of the tooth being treated. While rubber dams without latex are available, latex dams continue to be used. Contact with natural rubber latex products can produce hypersensitivity reactions, including irritant contact derma- titis, allergic contact dermatitis, and type I (IgE-mediated) hypersensitivity. As discussed, irritant contact dermatitis is a non-allergenic reaction to latex and/or the chemicals incorporated into natural rubber latex products during the manufacturing process. It is the most common reaction to latex products, and it is characterized by an erythematous, cracked,
and dry area confined to the immediate area in contact with the product. When this condition is caused by the use of latex gloves, it can be exacerbated by hand perspiration and frequent handwashing. There are no systemic manifestations of irritant contact dermatitis, but the associated irritation and discomfort can preclude one’s ability to practice dentistry until the area is healed. Because irritant contact dermatitis can disrupt the continuity of the skin, it may permit access of natural rubber latex molecules to deeper tissue layers and promote a progres- sive sensitization [37]. The clinical manifestations of latex-associated allergic contact dermatitis are more severe than those of irritant contact der- matitis, as the cutaneous areas involved can develop blisters that ooze and form a fragile crust that is easily disrupted. Pru- ritus is a common symptom of allergic contact dermatitis, but scratching will prolong the healing time. Discharge from open lesions can compromise the integrity of natural latex products and make wearing any gloves uncomfortable; clinicians should refrain from practice until the lesions are completely healed. Disruption of the epidermal surface that occurs during allergic contact dermatitis can also increase the risk of bacterial infec- tion and sensitization to natural rubber latex components. Clinicians who wear latex gloves and who develop symptoms of dermatitis should contact an allergist or dermatologist for skin patch testing to obtain a definitive diagnosis. (Interestingly, more than 50% of persons with latex allergy will also develop an allergy to certain fruit, most commonly avocado, banana, chestnut, and kiwi [38].) Initial treatment may include over- the-counter cortisone ointments, but severe cases of allergic contact dermatitis require the combined use of prescription topical cortisone preparations, antihistamines, and oral corticosteroids (e.g., prednisone). If staff or patients have a confirmed hypersensitivity to any component of natural rubber latex, these products should be avoided entirely in the office. As with any allergic reaction, an IgE-mediated response to natural rubber latex is associated with the highest degree of morbidity [39]. A type I hypersensitivity reaction to latex can vary from a localized reaction (e.g., urticarial lesions at the site of contact) to a more generalized reaction with distal lesions, rhinitis, and conjunctivitis. The most severe reaction, anaphy- laxis, is a possible but rare occurrence. While direct contact to the skin or mucosa is the most com- mon trigger of a reaction to latex, inhalation exposures are also possible. Natural rubber latex gloves often include powder on the interior to facilitate placement on the hands. This powder contains latex proteins, which can trigger an allergic response when inhaled by susceptible individuals. It is possible for these airborne particles to circulate and affect a sensitive patient or staff member in a completely different operatory.
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