Latex Allergy: Diagnosis, Prevention, and Management

1
Latex Allergy Diagnosis, Prevention, and
Management

• Tara Hata, MD
• Assistant Professor
• Dept of Anesthesia, UIHC
• March 27, 2001

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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

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Origin of Latex

• 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
• Proteins responsible for most generalized
  allergies
• 7 sensitizing proteins identified to date

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Manufacture of Latex Gloves

• 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
• Lowest levels in powderless gloves that undergo
  additional washing and chlorination

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Mechanisms of Exposure

• Cutaneous absorption, ie from gloves
• Inhalation via aerosolized proteins on powder
• Mucosal
• Vaginal/rectal exams, dental procedures, surgery
• Parenteral
• IVs, surgical wounds, severe dermatitis

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Hypersensitivity Classification

• Type I Immediate
• Type II Cytotoxic
• Type III Immune complex
• Type IV Delayed type

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Types of Latex Sensitivity

• Irritant contact dermatitis
• Type IV -- Delayed Hypersensitivity
• Type I --Immediate Hypersensitivity

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Irritant Contact Dermatitis

• 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
• Rx identify reaction, use alternative product

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Type IV -- Delayed Hypersensitivity

• 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

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Type I -- Immediate Hypersensitivity

• 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
• Onset within minutes
• Varied response local hives to anaphylactic
  shock
• Rx Antihistamines, steroids, anaphylaxis
  protocol
• Prevention avoid latex and areas where powdered
  gloves used

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Type I Mediators

• 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

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Cardiovascular Histamine Receptors

• Heart H1 coronary vasoconstriction
• H2 coronary vasodilation, tachycardia,
  inotropy
• Arteries H1 vasoconstriction
• H1,H2 vasodilation, hypotension
• Veins H1 increased permeability, edema
• H1, H2 vasodilation, pooling

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Pulmonary Histamine Receptors

• Bronchioles H1 Bronchoconstriction
• H2 Mucous secretion
• Vasculature H1 Increased permeability

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Gastrointestinal Histamine Receptors

• Smooth muscle H2 Constriction, cramping
• Mucosa H2 Acid secretion

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Cutaneous Histamine Receptors

• H1, H2 Vasodilation, increased permeability
• Pruritis, urticaria, angioedema

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Risk Groups for Latex Allergy

• Patients with history of multiple surgeries
• Meningomyelocele or severe urologic anomalies
• Health care workers
• Other occupational exposure
• Rubber product workers, hair dressers, house
  cleaners
• Individuals with atopy
• Hay fever, rhinitis, asthma, or eczema
• Patients with specific food allergies
• Banana, kiwi, avocado, chestnut, etc.
• Similar proteins

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Myelodysplastic Patients

• 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
• Other children at high risk
• multiple surgeries starting in neonatal period
• those with spinal cord injuries

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Health Care Workers

• Typically display a type IV reaction
• Can 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
• Progression from type IV to type I unpredictable

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Diagnosis of Latex Allergy

• 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
• Refer to allergist
• Skin testing
• In vitro testing

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Diagnosis by Skin Testing

• Diagnose Type IV delayed hypersensitivity
• Positive patch test
• Reaction appears anytime from 8 hours to 5 days
  later
• 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

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Diagnosis by In Vitro Testing

• 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
• EAST (Enzymeallergosorbent Test)
• Does not utilize radioactivity
• Sensitivity specificity of 80-85

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Prevention of Reactions in OR

• Identify latex sensitive patients
• Medic-alert bracelet
• Signs on hospital bed, room, and OR
• 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
• Post list of latex-containing devices
  alternatives
• FDA mandated labeling started February 1998
• Pretreat pts with positive hx

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Non-latex Equipment

• Disposable endotracheal tubes
• Esophageal stethoscopes
• Oral airways
• Suction catheters, Nasogastric tubes
• ECG pads
• Temp probes
• LMAs

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Potential Latex-Derived Products

• Gloves Tape, dressings
• Catheters, drains Tourniquets, elastic bandages
• IV ports, central lines Medication vials
• Syringes Nasal airways, masks, straps
• Breathing bag, bellows BP cuff tubing
• Stethoscope tubing Oximeter probe
• Check labels!

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Avoidance of Latex includes

• 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)

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Pretreatment

• Prophylaxis of anaphylaxis is controversial
• Efficacy unknown
• Anaphylaxis has occurred in pretreated pts
• May mask early signs
• 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)

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Recognition of Anaphylaxis

• Cutaneous
• Urticaria
• Flushing
• Diaphoresis
• Perioral / periorbital edema
• Conjunctival hyperemia
• Lacrimation
• Rhinitis

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Recognition of Anaphylaxis

• Respiratory
• Laryngeal edema
• Bronchospasm
• Pulmonary edema
• Cardiovascular
• Tachycardia, dysrhythmias
• Hypotension
• CV collapse

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Management of Anaphylaxis

• 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
• Antihistamine diphenhydramine 1 mg/kg
  H2 blocker optional
• Steroids hydrocortisone 1-4 mg/kg

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Again...

• 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
• Prophylax pts with hx of type I reaction
• Be prepared to treat anaphylaxis

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Conclusion

• 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 gloves with low extractable protein
  content
• Protect yourself
• Treat dermatitis
• Cover hand wounds with tegaderm