Presentation on theme: "Latex Allergy. INTRODUCTION NRL Allergy: it is a complex issue. Complex due to several reasons: Different types of materials are foreign to the human."— Presentation transcript:
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 % Water % Protein % 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 Content Depends 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 to [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 to [mg - EP/g-rubber] (See handout - Table 4: Yip, et al., 1994)
Creating Rubber from Latex
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
Types Glove Reactions: 3 Types –Irritant (Not allergic) vesiculation andcrackingErythema, dryness, scaling, vesiculation and cracking Skin irritation due to frequent glove-wearing, incomplete hand-drying, workplace chemicals, powder reactions –Delayed contact hypersensitivity (Not latex) Develops in 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 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 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 first Standardised Standardised Skin Test Reagents Now Available
Challenges Challenges 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
Challenges Challenges 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)
Allergies Management of Latex Allergies: 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 : :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 Latex 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.)
Allergic Considerations Hospital Management of Latex Allergic Patients: Special Considerations 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) What What is Anaphylaxis?
Anaphylaxis Anaphylaxis: Management Airway Adrenaline 1:1000 IM * –Only Hypotension / Bronchospasm –0.5mL (500µg) OR Adrenaline 1: mL (100µg) slow IVI –profound shock –anaesthesia Oxygen, ß2-agonists IV fluids (N/S, haemaccel) esIV steroids, antihistamines (Remove allergen) n Find the cause n Advise on prevention n Entire production line n Medic-Alert n Adrenaline (Epi-pen) n First-Aid education Avoid -blockers Avoid -blockers n ?Immunotherapy ACUTEINTERVAL 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:
Management Management 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
Hospital Hospital 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