Latex Allergy

INTRODUCTION

NRL Allergy: it is a complex issue. Complex due

to several reasons:

• Different types of materials are foreign to the human

body, can cause somewhat similar allergic reactions.

• Sensitization is in itself a complicated area for

medical diagnosis.

Introduction - cont’d.• Not all NRL products or NR products are processed

and manufactured the same way, including the same or similar products.

• There is confusion on what products are made from natural rubber or synthetic rubber or a combination of both.

• The term latex, itself, is used for different types of natural and synthetic “dipped” and “liquid” products.

Introduction - cont’d.

• Finally, the problems and confusion

between latex sensitization and

chemical sensitization exist.

Topics for Discussion

• Latex and its production

• Latex allergy and its ascent

• Diagnosing latex allergy

• Challenges & management of latex allergy

What is Latex?• Processed product from the cytosol of Hevea brasiliensis

found in Africa and Southeast Asia.

• Small rubber particles suspended in “serum”, with 1-2% protein

• > 200 polypeptides: > 50 allergenic

• Hev b 1,2, and 6: Major allergenic proteins

• Not be confused with petroleum-based synthetic rubbers.

• Chosen as glove material because of its excellent combination of non-porosity and flexibility

Latex exporters

Natural Rubber (2 Forms)

• Latex -- stable aqueous dispersion of polymer particles

• Coagulum -- bulk-phase elastomeric material

Raw Latex Composition

• Polyisoprene 31 - 26%

• Water 58 - 65%

• Protein 1.5 - 3.0%

• Carbohydrates, Lipids,Inorganics, Other ~ 4.0%

Possible NR Latex Additives

• For emulsion stabilization: ammonia (collection cups)

• Primary Preservatives: sodium sulfite or formaldehyde

• Secondary Preservatives: e.g., zinc dithiocarbamate, zinc oxide

Dry Natural Rubber Processing

• Coagulation: Addition of formic acid

• Autocoagulation of latex dispersion (cuplumps)

• Additional processing, including chopping, grinding, water washing, drying, heat (smoke) - stabilization, and sheeting or baling

Residual Protein ContentDepends on Processing

• Field processing of latex

“liquid or dry”

• Manufacturing procedures

– natural rubber latex (NRL) – dry rubber

NRL Proteins Characterization

• 50 to 100 identified in NRL

• Molecular weights 10 to 70 kDalton

• Not all exhibit IgE binding due to epitope differences

Extractable Protein (EP) Levels

• NRL - generally higher (concentrated)

• Dry NR - generally lower

(acidified, macerated, multiple water washing, heat processing)

EP in NRL Dipped Products

• Higher EP levels ~ allergic response in atopic

individuals – NRL dipped products - range of

concentrations– Less than 0.020 to 1.680

[mg-EP/g-rubber]

(See handout - Tables 1 & 2: Yip, et al., 1994)

EP in Dry NR Products

• Very low EP levels ~ weak to no allergic

response

– Dry Rubber - negligible to no EP– Less than 0.020 to 0.034

[mg - EP/g-rubber]

(See handout - Table 4: Yip, et al., 1994)

Creating Rubber from Latex

11

22

55

33

44

77

66

88

Latex allergy (to gloves etc)Hospital staff 10% latex allergic, often hand

eczema, atopics at increased risk • Symptoms:

– urticaria (75-100%)

– conjuctivitis (20-45%), rhinitis (15-50%)

– asthma (3-30%)

– anaphylaxis (6-8%)

Don’t despair!Use non-latex gloves (vinyl, nitril or plastic)Use non-powdered, treated latex gloves

Where is Latex Found?Where is Latex Found?• Emergency Equipment

– BP cuffs, stethoscopes, gloves, ET tubes, electrode pads, tourniquets, IV tubing, syringes, airways

• PPE– Gloves, goggles, masks, rubber aprons

• Hospital Supplies:– Anaesthetic masks, catheters, drains, injection ports, multi-dose-vial tops

• Office Supplies:– Rubbers, rubber-bands, mouse pads

• Household objects:– Car tyres, cycle handles, carpeting, swimming-goggles, racquet handles, shoe

soles, expanadable fabric (waistbands), dishwashing gloves, hotwater bottles, condoms, pacifiers, diaphragms, balloons, pacifiers, baby-bottle-nipples

Glove Reactions: 3 TypesTypes– Irritant (Not allergic)

• Erythema, dryness, scaling, vesiculation andvesiculation and crackingcracking• Skin irritation due to frequent glove-wearing, incomplete

hand-drying, workplace chemicals, powder reactions– Delayed contact hypersensitivity (Not latex)

• Develops in 24-48 hrs; lasts days-weeks

• Eczematous; often identical appearance to irritant reaction

• Chemical additives such as ammonia, antioxidants and accelerators (eg. thiurams and carbamates) are commonly implicated.

• Similar mechanism to watch contact allergy

– True latex allergy

Most adverse reactions to gloves are non-allergic

Any form of dermatitis increases risk of true latex sensitisation

Case 1: Ms FR 29F• Background:

– Dental practice secretary:

• Also sterilises equipment: frequent glove use

– Asthma / rhinitis

• Dental problems began 12/99

– Dyspnoea and an urticarial eruption locally

– Responded to Ventolin without need for Adrenaline or steroids.

Case 1: Ms FR 29F

• Further questioning:

– Asthma had been quiescent: No ventolin puffer at home

• However, 2-3 months needing ventolin 3 x / day 3 x / week at work

– Also, rhinitis became worse at work, changing from its usual seasonal periodicity

– Particular association of respiratory problems with glove-wearing (herself or colleagues)

Case 1: Ms FR 29F• Diagnosis:

– CAP: 0

– Latex SPT: 5mm

• Management

– No latex powder at work

– Antihistamines

– Optimise background asthma / rhinitis control

– Nasal steroids

– Medi-Alert bracelet

– No adrenaline given in absence of history of life-threatening reactions

Type I (IgE) Allergy Cascade

What Are the Features of Latex What Are the Features of Latex Allergy?Allergy?

• Contact urticaria

• Occupational rhinitis and asthma

• Angioedema / airway obstruction

• Anaphylaxis

Rising Latex Allergy

• Adoption of universal precautions since 1987

• Changes in latex antigenicity due to changes in manufacturing processes forced by rising demands for latex products: Less leaching

– 3000 x difference in latex antigen levels from different manufacturers

– ?Poorer processing in Asian factories: allergenic

• Increased diagnostic suspicion and better diagnostic tools

• Mirrors the unexplained general increase in all atopic diseases over the last few decades, particularly in developed nations.

Rising Allergy: Why?• Genetic factors:

– important, but don’t explain rapid rise• Atopic disorders: 1/3 (developed)• Life-style: “Dust-mite” households• Early infections:

: RSV : measles, hepatitis A, TB

• Vaccinations: ?BCG protective• Diet and intestinal microflora• Anthroposophic lifestyle:

– 13% vs 25% atopy (OR 0.6)– Less antibiotics, fewer vaccines, live lactobacilli

Prevalence of Latex Allergy

Levels and Routes of ExposureLevels and Routes of Exposure• Powdered gloves greatest culprit for rise in latex allergy

– Allergenic latex proteins fasten to powder particles

• Higher surface area of particles allows more efficent protein delivery to skin

– Particularly relevant in people with dermatitis or prior skin damage, a demonstrated risk factor for developing true latex allergy

• Also delivers latex protein across mucosae and serosae during operations and procedures such as catheterisation

• Aerosolisation of powder delivers latex antigens across respiratory membranes, inducing rhinitis and asthma

• ? Adjuvant effect of cornstarch powder

• Protein-poor powder-free latex gloves less sensitising than protein-rich powdered gloves*

* Levy DA et al. Powder-free protein-poor NRL latex gloves and latex sensitisation. JAMA 1999;281:988

Risks for Latex Allergy• Atopy (in 57%)

• Recurrent operations / instrumentations

– Spina bifida patients ++ (prevalence 28%-67%)

– Others e.g. congenital urinary abnormalities, cerebral palsy, quadriplegia

• Consider in any patient who develops peri-operative anaphylaxis

• Latex industry workers• Health workers: 10% sensitisation; 1-8% significant reaction

• Allergies to unusual foods

• Other people with latex glove exposure:

– Hairdressers, food-handlers, housekeepers,..

Case 2: Mr PE 43M

• Community nurse• Previously healthy except for hypertension treated

with coversyl (perindopril)• 4 yrs ago: Contact eczema with latex gloves• 2 yrs ago: Allergic rhinitis• Non-latex gloves

Mr PE 43M

• 1/97: Urticaria with facial swelling

• 5/97: Bronchospasm with glove “snapping”

• 10/97: Casualty after Indian meal

– Bronchospasm, urticarial rash, hoarseness

– Rx: phenergan, ventolin

Mr PE: Investigations

• Latex-specific IgE CAP: Positive (2)(SPT not performed)

• SPT to HDM, grasses: Positive

Cross reactions

• Latex is derived from a plant

- Related to other plants !

Diagnosis of Latex Allergy

• History +++

• Demonstrate allergen-specific IgE– False negatives for objective tests occur– History is final arbiter

• Finger-use and other challenges less commonly employed

Skin Prick Testing (SPT) vs. In-vitro Allergen-Specific IgE

• Skin prick testing is most sensitive– But increased reaction risk

• Blood testing (RAST,CAP) less sensitive

Do blood testing Do blood testing firstfirst

StandardisedStandardised Skin Test Reagents Now Available

ChallengesChallenges of Latex Allergy (I): OH & S

• No available synthetic gloves can match the elasticity, durability, resilience, affordability and impermeability of latex

• Nevertheless, double-gloving with synthetic gloves may offer similar protection against infectious agents, albeit with impaired tactile performance

ChallengesChallenges of Latex Allergy (II): Dollars

• Costs arise from:• the sensitisation of health care workers

• treatment of sensitised individuals; and

• changes required to minimise latex allergy sensitisation and reactions

• Up to 61% costs for surgical gloves. – Balance against long-term savings from reduced:

• treatment complications

• litigation

• workers compensation

• glove-powder-related adhesions (morbidity, further surgery)

Latex Lists

Latex Containing Latex FreeGloves Ansell Dermaprene

Vinyl exam glovesOximeter probes Datex, OhmedaBP cuff leads MedtelECG dots 3MIV line & bungs BraunSyringes TerumoAirways, masks, bags PromedicaCatheters CookTapes Micropore, 3MDressings Opsite

Management of Latex AllergiesAllergies: Staff & Workplace

• Glove Use:– Worker: Synthetic or non-powder latex-poor– Colleagues: Non-powdered latex-poor

• Gradual replacement of latex containing products with non-latex products where available and appropriate

• Powder: Nonpowder - 1987 65:35- 1999 50:50

Public Health:Preventing Latex Allergy

• Glove usage*:

– Where no infectious risk: synthetic gloves

– Where infectious risk: nonpowdered low-protein latex or double-synthetic gloving

• Handcare Risk sensitisation with damaged skin

– Oil-based creams increase allergen leaching

– Wash hands after removing gloves

*NIOSH Alert: Preventing allergic reactions to NRL in the workplace. MMWR 1987;36(Suppl 2):1S-18S

Public Health:Legislation

• 1997: Maximum allowable glove protein– ASTM: 200 g/g rubber– CEN/TC (Europe): 10 g/g rubber– AAAAI Joint Statement:

• “Only low-allergen and powder-free latex gloves should be purchased & used.”

• 1998: FDA Packaging– All medical devices coming in contact with the body must carry:

– Little compliance with disclosure of allergen levels– Use of “hypoallergenic” term not permitted

• Misleading, inconsistent

“This product contains Natural Rubber Latex”

Ward Preparation for Ward Preparation for Latex Allergic PatientsLatex Allergic Patients

• Synthetic gloves

• Single room (prepared & latex free)

• Damp dust surfaces

• Block air-conditioning ducts

• Signs for doors (“Latex Safe”) & records

• Plan all procedures

• Prepare to treat anaphylaxis

Support Groups

• E ducation for• L atex• A llergy• S upport• T eam and• I nformation• C oalition (inc.)

• www.latex-allergy.org

Hospital Management of Latex AllergicAllergic Patients: Special ConsiderationsConsiderations

• Venepuncture (tourniquets)• IV lines without latex ports• Medication vials: No latex stoppers• Synthetic gloves for internal examinations• Non-latex catheters, syringes, dressings, tapes• Oximeter probes• Sphygmomanometers: cotton-cloth cover• ECG dots• Stethoscopes• Kitchen staff: synthetic gloves; food allergies

Public Health:Preventing Latex Allergy (II)

• Interdepartmental latex committees:– Nursing, allergy, staff health, surgery, anaesthetics, OT,

purchasing, labs, housekeeping, kitchens,…

• Attend workplace education / training• Keep latex-free product registers• Encourage industry to label latex products• Pre-placement and routine staff screens

• Severe systemic allergic reaction

• Involves one or both of:– Respiratory difficulty (URT, asthma)– Hypotension

• Other allergic features often occur in association

• Usually immediate ( < 1/2 hour)– Rarely delayed (up to 6 hours)– Sometimes (~5%) biphasic (1h - 72 h)

WhatWhat is Anaphylaxis?

AnaphylaxisAnaphylaxis: Management

• Airway

• Adrenaline 1:1000 IM *

– Only Hypotension / Bronchospasm

– 0.5mL (500µg)

• OR Adrenaline 1:100001 mL (100µg) slow IVI

– profound shock

– anaesthesia

• Oxygen, ß2-agonists

• IV fluids (N/S, haemaccel)

• IV steroids, antihistamineses

• (Remove allergen)

Find the causeFind the cause Advise on preventionAdvise on prevention

Entire production lineEntire production line Medic-AlertMedic-Alert Adrenaline (Epi-pen)Adrenaline (Epi-pen) First-Aid educationFirst-Aid education Avoid Avoid -blockers-blockers ?Immunotherapy?Immunotherapy

ACUTEACUTE INTERVALINTERVAL

• Repeat adrenaline in 5 minutes if deteriorating• 10% of out-of-hospital anaphylaxes require repeat adrenaline shot

* Project Team of the Resuscitation Council (UK). The emergency medical treatment of anaphylactic reactions. J Accid Emerg Med 1999;16:243-247

ManagementManagement of Latex Allergies: Staff & Workplace (I)

– Same general principles as for patients– Safe Workplace

• Education and Training• Work environment modification

– Consider:

» all work areas that a worker needs to go to;

» patient movements

» other worker contacts; and

» common air conditioning areas.

– Housekeeping should be meticulously carried out to remove all traces of latex allergens.

– May require occupational rehabilitation (Rarely)

Sensitisation: Mechanisms

• Preclinical sensitisation may occur in early life– First exposures in infancy:

• Bottle nipples, pacifiers, balloons,…

• Quantity of latex and site / duration of contact important

Latex Questionnaire• Have you ever reacted to latex-containing

products?• Risks:

– Atopy 3 major surgery episodes

– Spina bifida

– Unusual food allergies

– HCW / At-risk occupation

– Perioperative anaphylaxis

Score > cutoff: Measure IgE to latex ; if POSITIVE, or persistent suspicion of latex allergy, refer for specialist review

HospitalHospital Management of Latex Allergic Patients

• Latex-safe environment– No powdered gloves: preferably, synthetic gloves only– Prepare OT and wards: no latex products

• Identify allergic patients:– Questionnaires– Investigate people with unexplained anaphylaxis / unusual

food allergies• Special labels for rooms and records• Admission to discharge planning• Plan all procedures• Pharmacological prophylaxis should be considered• Be prepared to treat anaphylaxis

Neonates with congenital abnormalities: Educate parents on latex

Summary

• Latex allergy is a major problem– Latex is ubiquitous & difficult to fully avoid

• Most adverse glove reactions are non-allergic– But irritant dermatitis can risk of latex sensitisation

• Latex allergy affects up to 8% of health workers• Risk factors include recurrent operations, atopy &

unusual food allergies

• We must use synthetic alternatives or low-allergen powder-free latex gloves