Cross-Infection Control Protocol Continued

LATEX ALLERGY IN DENTISTRY

Provided on behalf of the Quality Assurance Committee, ADA by Dr Michael J Aldred, Specialist in Oral Medicine and Oral Pathology

The universal adoption of the wearing of gloves in dentistry and other health professions has been accompanied by a rise in reports of allergy to natural rubber latex. Latex is also encountered in condoms and many household items. About 10% of dental health personnel may report reactions to latex products and many of these can be demonstrated to have Type I hypersensitivity to latex.

Latex can be encountered in the dental surgery in:

Latex is found in many items used in hospital clinics, wards and operating theatres. These items include:

Risk factors for latex allergy include:

Reactions to latex and, in particular, the wearing of gloves come under three categories:

Irritant contact dermatitis is not uncommon in health care workers and may be associated with frequent hand-washing and inefficient drying of the skin. This may increase the passage of latex allergens across the compromised skin barrier.

Type IV delayed type hypersensitivity reactions tend to appear 2-4 days after exposure to rubber products, producing erythema of tissues having been in direct contact with the material. The materials used in preparation of latex products are considered to be the major cause of a Type IV response.

Type I immediate hypersensitivity reactions are, as the name implies, immediate in their onset. The reactions can take the form of itching, a generalised rash, rhinitis, conjunctivitis, wheezing, palpitations, dizziness, laryngeal oedema and anaphylactic shock leading to death if not treated urgently. People who have Type I hypersensitivity to latex can develop anaphylactic reactions to latex simply on entering dental surgeries and operating theatres where there is a significant load of latex allergen.

Testing for latex allergy
Testing for latex allergy is problematic. Patch testing for Type IV reactions can be performed, but is difficult to standardise because of variations in the latex preparations used. Intradermal injection carries the risk of inducing anaphylactic shock. For patients with Type I reactions IgE radioallergosorbent testing (RAST) can be carried out, but false positives are not uncommon. It would be sensible to regard any person with symptoms of Type I hypersensitivity to latex (as outlined above) as being allergic.

Minimising latex allergy
The use of powdered gloves is a potent means of spreading an aerosol of latex into the environment. The latex protein binds to the corn starch used to powder the gloves and is then dispersed widely within a dental surgery or operating theatre. The use of unpowdered gloves is recommended to minimise spread of latex particles into the air and hence the general environment. "Low-allergen" latex gloves are available but there is little certainty that these offer any real benefit.

Dental treatment of patients with latex allergy
Non-latex (vinyl, neoprene, neolon, nitrile-based or polymer gloves) should be available in all dental practices. All patients claiming to be sensitised to latex should have their claims treated with due consideration.

To reduce cross-infection, gloves must be worn – latex allergy in a patient is not a reason to avoid wearing gloves. Patients with Type IV delayed hypersensitivity allergic contact dermatitis should not be treated with rubber gloves; other latex-containing materials and equipment should also be avoided. For endodontic treatment and other procedures normally carried out under rubber dam, an alternative dam can be fashioned from vinyl sheet or a vinyl glove.

Patients with Type I hypersensitivity reactions need to be treated with great care, adopting the measures referred to above. It is probably advisable that treatment not be offered in a surgery where powdered gloves are routinely used. It is mandatory to have appropriate emergency treatment available (adrenaline and oxygen) and staff should be trained in resuscitation techniques. Treatment at the beginning of the day is preferred, before environmental levels of latex allergens rise as activity in the surgery increases. Type I hypersensitivity patients should only be treated where the dentist and other staff are confident in their ability to manage patients who develop problems. If in any doubt, the patient should be referred for appropriate management, probably in a hospital setting.

Medico-legal and worker's compensation aspects The adoption of a policy of using non-powdered gloves to minimise exposure to latex allergens in the workplace should reduce the likelihood of an employer being sued if any employees develop latex allergy in the course of their work. Failure to act upon a patient's claim that they are allergic to latex would be difficult to defend.

Spina A M, Levine H J. Latex allergy: a review for the dental professional. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999; 87: 5-11)