Prevalence of latex allergy in a dental school
Constance H Katelaris, Richard P Widmer and Ross M Lazarus
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Abstract - Introduction - Methods - Results - Discussion - Acknowledgements - References - Authors' details
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©MJA1997
It is now recognised that latex allergy is a particular problem for
certain "at risk" groups, including health care workers, patients
with spina bifida or other spinal cord abnormalities and patients who
have had multiple operations. In addition, atopic individuals are
more likely to develop IgE antibodies to latex protein with increased
exposure.2
The clinical manifestations of type I hypersensitivity reactions to
latex protein are wide ranging, from contact urticaria to
life-threatening anaphylaxis and death. There is now little doubt
that at least some episodes of intraoperative anaphylaxis have
occurred because the patient has been sensitised by latex and reacts
after mucosal contact with the operating staff's gloves. This has led
to some institutions providing latex-free operating suites.
No studies of latex allergy in Australia have been published. In this
study, we examined the prevalence of latex glove-associated
symptoms in the staff of a dental institution.
Dental workers are an excellent group for studying the question of
latex glove-related symptoms as they may wear gloves for 8-10 hours
daily, 4-5 days a week, giving them a much greater degree of exposure to
latex than most other health care workers.
Personnel surveyed included general and specialist dentists,
chairside assistants, dental technicians and dental hygienists.
Glove dermatitis: Report of the presence of two or
more symptoms of itching, redness and rash (excluding hives) which
had been present long term.
Latex hypersensitivity: Report of the prompt onset
(within 30 minutes of wearing gloves) of hand urticaria with or
without the occurrence of allergic rhinoconjunctivitis, lower
respiratory tract symptoms such as cough, wheeze or chest tightness,
generalised cutaneous itch or urticaria, or upper-airway oedema,
hypotension, dizziness or collapse.
Atopy: Present if the respondent gave positive
answers to any two or more questions on a history of asthma, allergic
rhinitis or atopic dermatitis.
Almost all of the youngest staff responded, whereas among older
individuals response rates were as low as 32% for age 51 or 60. As three
cells of this Table had expected counts of less than five, we used
Fisher's exact test, which showed a significant association (P < 0.00001) between non-response and age group.
Men were significantly more likely to respond than women (chi-squared = 26.1; P < 0.00001). The
job categories with the highest non-response rates were the small
group of registered nurses (58.3%) and the general dentists (43.9%).
Evidence that response rate was associated with job category was weak
(chi-squared = 11.1; P = 0.05),
and this question was not answered by a substantial proportion of
respondents.
Two-thirds of the study group spent more than half their working day
wearing gloves. Symptoms attributed to glove use were reported by
one-third of subjects, with itch and redness being the commonest
symptoms reported.
Table 2 (above) compares selected demographic and
allergic characteristics of the 39 subjects (22%) who satisfied the
criteria for glove dermatitis with the 16 subjects (9%) fulfilling
the criteria set for latex hypersensitivity. Other symptomatic and
allergic characteristics of the 16 dental workers with latex
hypersensitivity are compared with those of the rest of the
respondents in Table 3 (below). Almost all of
the individuals reporting latex-allergic symptoms also met the
criteria for glove dermatitis. Nineteen per cent of the
latex-allergic group reported food allergy, although none reported
symptoms with foods such as avocado, banana, nuts or soy products,
foods which have been described previously as cross-reacting with
latex protein.
Fisher's exact test was used to test the hypothesis that atopic
diathesis was associated with latex hypersensitivity and glove
dermatitis. Atopy was associated with both latex hypersensitivity (P = 0.014) and with glove dermatitis (P = 0.006).
Subjects who reported experiencing symptoms of either glove
dermatitis or latex-allergic symptoms were asked to indicate any
action they had taken; of those with glove dermatitis 59% had never
sought professional help and one-third of the latex
hypersensitivity group had not sought medical attention.
The distribution of non-response rates by demographic
characteristics shown in Table 1 indicates
that the volunteer sample was not fully representative of the study
population. In particular, female staff, older staff, general
dentists and registered nurses were less likely to respond. As a
result of these sampling biases, our findings may not be fully
generalisable to dental workers. For example, if staff experiencing
symptoms were more likely to volunteer for the survey, then our rates
will be overestimates of true prevalences. Our results should be
interpreted with caution, and future surveys should aim to obtain
more representative samples.
Relying on questionnaire data alone to determine hypersensitivity
reactions has obvious shortcomings. Contact urticaria with glove
use may be caused by non-IgE-mediated mechanisms, so our findings may
overestimate the prevalence of latex allergy. However, the
occurrence of symptoms in other organ systems soon after gloves are
used is highly suggestive of an IgE-mediated allergic reaction.
Confirmation of this prevalence rate will require some objective
measure of IgE-mediated hypersensitivity such as skin testing with
appropriate extracts, or in-vitro assay of specific IgE antibodies
to the latex allergens.
Our prevalence rate of 9% for latex allergy among dental personnel is
comparable with, although lower than, rates reported elsewhere. In a
similar questionnaire survey without objective testing, Berky et
al.4 reported "symptoms of an
allergic nature" in 13.7% of 1043 United States Army dental officers.
However, this figure included those reporting delayed symptoms as
well as those reporting localised contact urticaria or generalised
urticarial reactions. Furthermore, a third of those reporting
symptoms were unable to be classified as having either contact
dermatitis or latex allergy from their questionnaire responses.
Only 25% of those reporting latex allergy in the Berky study had
consulted a physician.
Rankin et al.5 also conducted
a questionnaire survey in a large dental facility in the US, obtaining
a 15% prevalence of adverse reactions to latex gloves (Table 4).
A number of studies4-6 have
confirmed a relationship between atopy and latex allergy (Table 4). We also found a significant
association when atopy was defined by our criteria (reported
presence of any two of asthma, allergic rhinitis or atopic
dermatitis).
Walsh et al.7 examined
factors influencing the wearing of protective gloves in general
dental practice in Brisbane. Of 201 dentists who replied to a survey,
84.6% (170) reported that they routinely used gloves in their
practice, compared with 13.9% (28) who reported that they did not.
Reasons given for not wearing gloves included reduced sensation,
reduced movement, low infection risk, skin reaction, patient
acceptance and cost.
Our results imply that there is a high rate of glove-related symptoms,
particularly of glove dermatitis, in this dental workforce. This
indicates a need to educate this occupational group about proper hand
care as repeated washing, scrubbing and numerous glove changes
contribute to hand irritation.
Latex allergy has many implications for health care workers which
extend beyond the occupational setting. Most reports of
life-threatening anaphylactic reactions during surgery and other
procedures have involved sensitised health care workers.8 These individuals need to know the
risk they run when they themselves are patients. Mucosal contact with
latex appears to be a far more potent trigger for anaphylactic
reactions than cutaneous contact. People with latex allergy must be
given anaesthesia and surgery in a totally latex-free environment.
Atopic individuals appear to be especially at risk for sensitisation
to the latex protein. Adequate counselling about occupational
exposure and advice about methods of minimising the risk need to be
considered in view of this and other studies. Latex gloves from
different sources vary in the amount of latex protein detectable on
the surface.9 Presumably,
those with less cause less sensitisation and should be preferred in a
workplace where glove use is mandatory.
Department of Paediatric Dentistry, Westmead Dental School,
Sydney, NSW.
Department of Public Health and Community Medicine, University of
Sydney, Sydney, NSW.
Reprints: Dr C H Katelaris, Department of Immunology,
Westmead Hospital, Westmead, NSW 2145.
©MJA 1997
<URL: http://www.mja.com.au/>
© 1997 Medical Journal of Australia.
Abstract
Objective: To determine the prevalence of latex
allergy in dental workers.
Design: Questionnaire survey of staff of a dental
school.
Setting: The Westmead Dental School, a large dental
facility in western Sydney.
Participants: 230 staff members of the Westmead
Dental School (consisting of general and specialist dentists,
chairside assistants and registered nurses, laboratory
technicians, dental therapists and hygienists) received
questionnaires.
Main outcome measures: The prevalence of latex
allergy, defined by prompt onset of hand urticaria with or without
generalised symptoms, and the prevalence of hand dermatitis and
other glove-related symptoms. Also, the relationship between latex
allergy and associated atopic status.
Results: 177 staff (77%) responded by the set
collection date; 33% reported symptoms related to wearing gloves and
22% satisfied the criteria for glove dermatitis. Sixteen
respondents (9%) reported characteristics suggestive of latex-
glove allergy.
Conclusions: Confirmation of the 9% prevalence of
latex allergy among dental workers will require further studies
incorporating an objective measure of IgE-mediated
hypersensitivity.
Introduction
Adverse reactions to rubber products have been recognised for many
years, and irritant reactions and cell-mediated hypersensitivity
reactions such as contact dermatitis are well described. The latter
are thought to be caused by one or more low-molecular-weight chemical
compounds added in the rubber-making process.1
Methods
All 230 staff of the Westmead Dental School, a large dental facility in
western Sydney, New South Wales, were surveyed by anonymous
questionnaire distributed during Feburary 1995, with a three-week
collection time allocated.
Questionnaire details
The questionnaire was divided into four sections.
Definitions
Statistical analysis
All statistical analysis was performed using the SAS package.3 Fisher's exact test was used to
test for marginal association in all two-way tables. For other
contingency tables, the chi-squared statistic was used to test for marginal association unless otherwise
specified. The distribution of demographic characteristics of the
staff of the Dental School was used to estimate response rates in order
to test for sampling (volunteer) bias.
Ethical approval
Ethics approval was obtained from the Westmead Hospital Human
Research Ethics Committee.
Results
Completed questionnaires were received from 177 of the 230 staff
(77%) by the closing date. Table 1 (below)
shows the distribution of non-response from the population, sampled
by age group, by sex and by job category. Not all respondents answered
all the demographic questions and the response rates are slightly
underestimated because 2.3% of age, 8.5% of sex and 14.1% of job
category data were missing. It was not possible to compare
non-respondents with respondents as the questionnaires contained
no personal identifying data. Year of graduation was the question
most frequently not answered (32 of 177 questionnaires [18%]).
Discussion
Our findings indicate a significant occupational health problem
among dental personnel wearing latex gloves. In our study, 33% of
those surveyed reported some symptoms with glove use; 22% met
criteria for glove dermatitis and 9% for latex allergy.
Acknowledgements
We would like to thank Maggie Melink for valuable assistance and the
staff of the Westmead Dental School for their cooperation.
References
(Received 19 Sep 1995, accepted 6 Apr 1996)
Authors' details
Department of Immunology, Westmead Hospital, Sydney, NSW.
Constance H Katelaris, PhD, FRACP, Senior Consultant.
Richard P Widmer, MDSc, FRACDS, Associate Professor.
Ross M Lazarus, MB BS, FAFPHM, Lecturer.
Received 17 April 2021, accepted 17 April 2021