Transcript Latex allergy: Diagnosis, Prevention, and Management

Latex Allergy: Diagnosis,
Prevention, and Management
Tara Hata, MD
Assistant Professor
Dept of Anesthesia, UIHC
March 27, 2001
History of Latex Allergy
1933 Contact dermatitis to gloves
1979 Contact urticaria
1982 Identified IgE antibodies to latex proteins
1989 Anaphylaxis and death from latex exposure
Association with spina bifida or severe GU anomalies
1997 Reports to FDA total 2300 allergic reactions
(225 anaphylaxis, 53 cardiac arrests, 17 deaths)
1998 FDA mandates labeling of medical products
Origin of Latex
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Latex is sap from rubber tree, Hevea brasiliensis
60% H2O, 35% rubber, 5% protein
Rubber molecule: cis-1,4-polyisoprene
Chemicals added during production
 Preservatives
(ie: ammonia), accelerators (ie: thiurams),
antioxidants (phenylenediamine), vulcanizing
compounds (ie: sulfur)
 May elicit delayed hypersensitivity
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Proteins responsible for most generalized allergies
7
sensitizing proteins identified to date
Manufacture of Latex Gloves
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Protein content can vary 1000-fold among lots
May vary 3000-fold among manufacturers
Powdered examination gloves have highest protein
content and allergen levels
 Cornstarch
particles adsorb latex allergens
 Particles aerosolized: assoc with respiratory symptoms
 Particles also contaminate clothing
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Lowest levels in powderless gloves that undergo
additional washing and chlorination
Mechanisms of Exposure
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Cutaneous absorption, ie: from gloves
Inhalation via aerosolized proteins on powder
Mucosal
 Vaginal/rectal
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exams, dental procedures, surgery
Parenteral
 IVs,
surgical wounds, severe dermatitis
Hypersensitivity Classification
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Type I
Type II
Type III
Type IV
Immediate
Cytotoxic
Immune complex
Delayed type
Types of Latex Sensitivity
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Irritant contact dermatitis
Type IV -- Delayed Hypersensitivity
Type I --Immediate Hypersensitivity
Irritant Contact Dermatitis
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Most frequent reaction to latex products
Sxs/signs: scaling, drying, cracking of skin
Results from direct action of latex and chemicals
Not a true allergy - no immunologic mechanism
 However
breakdown in skin integrity enhances
absorption of latex proteins
 Accelerates onset of sensitivity/allergy
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Rx: identify reaction, use alternative product
Type IV -- Delayed Hypersensitivity
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Synonyms: T-cell mediated contact dermatitis,
allergic contact dermatitis
Most common immune response to gloves
Sxs/signs: mild to severe dermatitis (itching,
blistering, crusting); appears 6-72 hrs after contact
Cause: processing chemicals in gloves;
mediated by T lymphocytes (not antibodies)
Rx: Identify chemical and use alternative product
Patients may progress to Type I allergy
Type I -- Immediate Hypersensitivity
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Synonyms: IgE mediated anaphylactic reaction
Cause: proteins in latex
 Antigen
induces production of IgE; re-exposure to
antigen triggers cascade: release of histamine,
arachidonic acid, leukotrienes, prostaglandins
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Onset within minutes
Varied response: local hives to anaphylactic shock
Rx: Antihistamines, steroids, anaphylaxis protocol
Prevention: avoid latex and areas where powdered
gloves used
Type I Mediators
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Histamine and tryptase release common to type I and IV
Prostaglandins, leukotrienes, eosinophilic chemotactic
factor, platelet activating factor
 potent bronchoconstrictors, vasodilators
Cytokines released minutes later also cause inflammatory
effects
Cardiovascular Histamine Receptors
Heart
H1
H2
Arteries
H1
H1,H2
H1
coronary vasoconstriction
coronary vasodilation,
tachycardia, inotropy
vasoconstriction
vasodilation, hypotension
increased permeability, edema
H1, H2
vasodilation, pooling
Veins
Pulmonary Histamine Receptors
Bronchioles
H1
H2
Bronchoconstriction
Mucous secretion
Vasculature
H1
Increased permeability
Gastrointestinal Histamine Receptors
Smooth muscle
H2
Constriction, cramping
Mucosa
H2
Acid secretion
Cutaneous Histamine Receptors
H1, H2
Vasodilation, increased permeability
Pruritis, urticaria, angioedema
Risk Groups for Latex Allergy
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Patients with history of multiple surgeries
 Meningomyelocele
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Health care workers
Other occupational exposure
 Rubber
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product workers, hair dressers, house cleaners
Individuals with atopy
 Hay
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or severe urologic anomalies
fever, rhinitis, asthma, or eczema
Patients with specific food allergies
 Banana,
kiwi, avocado, chestnut, etc.
 Similar proteins
Myelodysplastic Patients
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Prevalence of latex allergy is 18-64%
Type I reactions more common
Predisposing factors
 multiple
surgeries
 daily catheterizations / stoma care
 presence of atopy is synergistic factor
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Other children at high risk
 multiple
surgeries starting in neonatal period
 those with spinal cord injuries
Health Care Workers
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Typically display a type IV reaction
 Can
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include conjunctivitis, rhinitis, dermatitis
1998 study: prevalence of immediate sensitivity in
anesthesiologists & CRNAs 12-16%
 Over
80% of those sensitized had no sxs yet
 Risk factors: hx atopy, skin sxs with latex gloves,
tropical fruit allergies
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Progression from type IV to type I unpredictable
Diagnosis of Latex Allergy
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*Clinical history (ask the right questions)
 Myelodysplasia
/ urologic anomalies
 Multiple surgeries
 Chronic occupational exposure
 Previous reactions to latex products (type I)
 Certain food allergies
 Atopy
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Refer to allergist
 Skin
testing
 In vitro testing
Diagnosis by Skin Testing
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Diagnose Type IV delayed hypersensitivity
 Positive
patch test
 Reaction appears anytime from 8 hours to 5 days later
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Diagnose Type I allergy
 Skin
prick test using antigens from glove products
 Gold standard
 Positive test: wheal and flare (c/t + and - controls)
 Sensitivity and specificity around 98%
 May result in severe reaction
Diagnosis by In Vitro Testing
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No risk to patient
RAST (radioallergosorbent test)
 Measures
amount of IgE Ab to latex in serum
 Most labs must send out
 Takes 5-10 days
 Sensitivity 80-90%
 Specificity 60-90%
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EAST (Enzymeallergosorbent Test)
 Does
not utilize radioactivity
 Sensitivity & specificity of 80-85%
Prevention of Reactions in OR
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Identify latex sensitive patients
 Medic-alert
bracelet
 Signs on hospital bed, room, and OR
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Schedule as 1st start in OR
Use latex free environment
 For
pts with hx of type I or type IV reactions
 Meningomyelocele or urologic anomalies
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Post list of latex-containing devices & alternatives
 FDA mandated
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labeling started February 1998
Pretreat pts with positive hx
Non-latex Equipment
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Disposable endotracheal tubes
Esophageal stethoscopes
Oral airways
Suction catheters, Nasogastric tubes
ECG pads
Temp probes
LMAs
Potential Latex-Derived Products
Gloves
Catheters, drains
IV ports, central lines
Syringes
Breathing bag, bellows
Stethoscope tubing
Tape, dressings
Tourniquets, elastic bandages
Medication vials
Nasal airways, masks, straps
BP cuff tubing
Oximeter probe
*Check labels!
Avoidance of Latex includes:
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Avoiding skin contact: BP/stethoscope tubing, IV
tourniquets
Remove stoppers from multi-dose med vials
Tape latex injection ports on IV tubing, central
lines, IV fluid bags
Use latex free syringes (remember the epidural &
spinal trays)
Pretreatment
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Prophylaxis of anaphylaxis is controversial
 Efficacy
unknown
 Anaphylaxis has occurred in pretreated pts
 May mask early signs
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Pretreat pts with hx of Type I sxs
Start prophylaxis preop and continue x 24 hr
 Diphenhydramine
1 mg/kg q 6 hr IV or PO
 Methylprednisolone 1 mg/kg q 6 hr IV or PO
 Cimetidine 5 mg/kg q 6 hr IV or PO (up to 300 mg)
Recognition of Anaphylaxis
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Cutaneous
 Urticaria
 Flushing
 Diaphoresis
 Perioral
/ periorbital edema
 Conjunctival hyperemia
 Lacrimation
 Rhinitis
Recognition of Anaphylaxis
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Respiratory
 Laryngeal
edema
 Bronchospasm
 Pulmonary edema
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Cardiovascular
 Tachycardia,
 Hypotension
 CV
collapse
dysrhythmias
Management of Anaphylaxis
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Remove antigen
100% oxygen
IV volume expansion (up to 50 ml/kg)
D/C or adjust anesthesia
Epinephrine
 Bronchospasm
or hypotension: 0.1-5 ug/kg IV
 Cardiac arrest: peds: 10 ug/kg, adults: 0.5-2 mg IV
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Antihistamine: diphenhydramine 1 mg/kg
H2 blocker optional
Steroids: hydrocortisone 1-4 mg/kg
Again…...
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Identify those pts at high risk
For myelodysplastic & GU anomaly pts, as well as
those with hx of type I sxs:
 Label
pt, chart, pt room, OR as latex free
 Use latex precautions
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Prophylax pts with hx of type I reaction
Be prepared to treat anaphylaxis
Conclusion
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Most important step is avoidance of exposure in
susceptible patients
With universal precautions, the problem will likely
worsen
Hospitals should strive for low allergen
environments
 Powderless
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gloves with low extractable protein content
Protect yourself
 Treat
dermatitis
 Cover hand wounds with tegaderm