|
Source To Surgery - February 1995, Vol. 3 Issue I
Diagnosis of Latex Allergy
Kevin J. Kelly, MD, Director of Pediatric Allergy/lmmunology
Medical College of Wisconsin and Children's Hospital of Wisconsin,
Milwaukee, USA
Since the first report of contact urticaria to natural rubber products
in 1979, a series of serious life-threatening allergic reactions has
been reported worldwide.
Symptoms range from contact urticaria, upper and lower airway allergy,
to life-threatening anaphylaxis. These patients are allergic to natural
latex protein as a result of exposure in their job or through daily
medical care.
Latex protein hypersensitivity has recently been implicated as a major
public health problem facing the medical, surgical and medical
manufacturing industry.
Risk Groups and Risk Factors
Specific groups have been identified to be at high risk of sensitization
to latex protein. However, latex allergy is not restricted to
patients from these high-risk groups. In a report of life-threatening
anaphylactic reactions related to air contrast barium enemas, most of
the patients experiencing reactions were not from high-risk groups.
There is no accurate prediction of the proportion of the population that
will become sensitized over time.
Health Care Professionals. From 2.9-16% of health care
professionals have been sensitized to latex protein. Female personnel
with intense exposure to latex (e.g., surgeons and theatre nurses) and
atopic individuals are at highest risk. A contact or irritant dermatitis
often precedes the development of immediate hypersensitivity in health
care professionals and others who are sensitized via latex gloves.
Patients. In the USA, the sensitization rate for patients with
spina bifida has ranged from 18-68%. The risk for atopic patients is
approximately 3.8% while the general population seems to be sensitized
at a rate of less than 1/1000.
If a medical history consistent with latex allergy is obtained (Table
1), elective surgery should be cancelled until confirmatory tests can be
performed. It is prudent to assume that all patients with spina bifida
are sensitized to latex. Therefore the usefulness of latex testing in
this group is practically nonexistent.
Table 1
Manifestations of Allergy Associated with Latex Contact
- Pnuritus
- Erythema
- Non-urticarial rash
- Urticaria - local (hands) or generalized
- Angioedema
- Rhinoconjunctivitis
- Dyspnea
- Asthma/bronchospasm
- Stridor
- Hypotension
- Anaphylaxis - intraoperative
- Death
|
IgE-Mediated Hypersensitivity
Latex contains multiple proteins, lipids, and cis-1,4 polyisoprene, the
major component for which it is harvested commercially to manufacture
rubber products. As latex is a mixed component cytosol, many residual
nonessential components are retained in the finished rubber product. In
addition, over 100 different chemicals may be used in the latex
manufacturing industry. However, neither the chemicals nor polyisoprene
appear to be the offending antigens in latex immediate hypersensitivity.
IgE-mediated hypersensitivity develops in response to water-soluble
constituent proteins that remain in the latex following the
manufacturing process.
Allergenic Proteins
Allergenic proteins reacting with IgE from sera of sensitized patients
range in size from 14 kD to over 100 kD. With more than 200 proteins of
11 different molecular weight bands and several uncharacterized loF
molecular weight peptides, definitive testing for latex allergy is
inconsistent and difficult. Over 50 of these proteins have been shown tc
have allergenic potential.
The route of sensitization (e.g., skin, mucosa, intravascular), the
source protein (i.e., glove or other product), the latex type (e.g., low
ammoniated, high ammoniated), and individual immune responses may result
in variations in the severity of the reaction. For example, a health
care professional may react to antigen from only one glove type and to
different antigenic determinants than a patient with spina bifida.
Diagnosis
The diagnosis of protein hypersensitivity begins with a relevant history
with heightened suspicion if a patient has experienced angioedema,
pruritus, urticaria, rhinitis, conjunctivitis or asthma associated with
condoms, balloons, rubber gloves or any object containing latex. If a
positive history is obtained, diagnostic testing is the next step.
Latex sensitivity tests. Confirmation of latex sensitivity includes:
- skin prick and patch testing for immediate wheal and flare response
(skin prick is the most sensitive test)
- serological tests for latex-specific IgE
- basophilhistaminerelease
- Iymphocyte proliferation
- flow cytometry
- immunoblot
- provocation tests
- Iatex glove "use" tests.
A patient should be considered sensitized to latex if the history and
one confirmatory test are positive.
Care of the Latex-Sensitized Patient in the Operating Theatre
It is necessary to develop a protocol to maintain a latex-free surgical,
inpatient and outpatient environment for the sensitized patient.
Aerosols. Latex protein may be present in the air of the
operating theatre as an aerosol and, like pollen, may be inhaled as an
aeroallergen. Starch donning powder on gloves adsorbs and binds protein
readily and may have a role in making latex antigen airborne.
Low-Allergen Gloves
The use of latex examination and surgical gloves has increased
dramatically since the introduction of universal precautions in hospital
and clinic settings. This increased exposure may account for the
emergence of latex allergy as the threshold for sensitization has been
surpassed. The contribution of changes in the allergenicity and
processing of latex to increased sensitization has not been established.
Thus, use of a glove with a low allergen content may be desirable.
"Hypoallergenic" Gloves. In the USA, the FDA has recommended that
the misleading term "hypoallergenic" be removed from gloves. This label
was introduced for consumers who developed either an irritant or contact
dermatitis from the accelerator or antioxidant chemicals used in the
vulcanizing of rubber gloves. This is a distinct reaction and is not
IgE-mediated. Some patients with immediate hypersensitivity may wrongly
assume that these gloves are safe. One potential problem introduced by
this response from the FDA is less quality control in glove
manufacturing, because no substitute labeling has been proposed.
Synthetic gloves. Many companies have responded to the allergen
problem by manufacturing synthetic, latex-free gloves (e.g., DermaPrene,
Ansell International; Tactylon: Tactyle Technologies; Nealon: BD).
Treatment of Anaphylaxis
Treatment of anaphylaxis includes the use of adrenaline, oxygen and
isotonic fluids. Since anaphylactic reactions may become biphasic, with
recurrence within 8-12 hours, close observation is warranted after a
reaction. Corticosteroids and H1 and H2
antagonists are indicated for use with inhaled B-adrenergic agent if the
patient has bronchospasm. If a patient is on a B-blocking agent (e.g.,
propanolol), the response to standard doses of adrenaline may be
incomplete. Higher doses of adrenaline and the use of glucagon may
overcome this incomplete response. Confirmation of mast cell
degranulation can be confirmed with a serum tryptase level, which will
peak 1-2 hours after the anaphylactic reaction.
Further Reading
Eghrari-Sabet JS, Slater JE. Latex allergy: a potentially serious
respiratory disorder. J. Respir Dis 1993; 143: 473-82.
Kelly KJ, Kurup VP, Zacharisen MC, Resnick A, Fink JN. Skin and
serolosgic testing in the diagnosis of latex allergy. J Allergy Clin
Immunol 1 992; 91: 1140-5.
Leynadier F. Pesquet C, Dry J. Anaphylaxis to latex during surgery.
Anaesthesia 1989; 44: 547-50.
Own by D, Tomianovich M, Sammons N. McCullough J. Anaphylaxis associated
with latex allergy during barium enema examinations. Am J Roent 1991;
156: 903-8
Slater J. Allergic reactions to natural rubber. Ann Allergy 1992; 68:
203-12.
|
