A Practical Approach to the Allergic Employee

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A Practical Approach to the Allergic
Employee

• Reid Boswell, M.D., M.P.H.
• Medical Director
• Mount Auburn Hospital Occupational Health
  Services
• CareGroup Occupational Health Network

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OrTales of Woe from the Annals of the
Accidental Allergist
3

• Definitions
• Overview of Occupational Allergies
• Lab Animal Allergies
• Latex Allergies
• Chemical Allergies
• Managing Employees with Allergic Symptoms
• Case Studies

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Definitions

• Allergy
• Irritation
• Cacosmia
• Psychosomatic illness
• Frank malingering

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Allergy

• Hypersensitivity reaction resulting from
  specific interactions between antigens
  (allergens) and either antibodies or sensitized
  lymphocytes.

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Gel and Coombs Classification of Allergic
Reactions

• Type 1 Immediate, IgE mediated. Results in
  release of inflammatory mediators (histamine,
  leukotrienes, etc.). Examples include urticaria,
  anaphylaxis
• Type 2 Cytotoxic. Antigen-antibody complex
  results in activation of cytotoxic cells.
  Examples transfusion reactions, Goodpastures
  syndrome.

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Gel and Coombs, continued

• Type 3 Immune complex reactions resulting in
  deposition of soluble complexes in tissue.
  Examples vasculitis, serum sickness (drug
  reactions), SLE
• Type 4 Delayed , cell-mediated caused by
  sensitized lymphocytes. Examples tuberculin
  reaction, RA, sarcoidosis, Wegeners
  granulomatosis.

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Clinical Manifestations

• Rhinoconjunctivitis
• Sneezing
• Nasal congestion
• Itchy, watery eyes

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Clinical Manifestations

• Upper airway congestion
• sore throat
• sensation of throat tightening
• laryngitis
• dry cough

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Clinical Manifestations

• Dermatologic
• Urticaria (hives) usually type I reaction
• Itchy, red papules (maculopapular eruption) at
  site of contact contact dermatitis, usually
  type IV reaction (similar to poison ivy).

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Clinical Manifestations

• Asthma Wheezing, chest tightness, and cough
  caused by spasm of small airways, which is
  relieved by bronchodilators.
• Diagnosed by pre and post bronchodilator
  pulmonary function tests.
• Asthma may persist even after removal from
  exposure.
• Up to 15 of all asthma in industrialized
  countries is due to occupational exposures.

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Clinical Manifestations

• Most workers have a combination of symptoms.
• Symptoms often progress from mild rhinitis to
  severe asthma with continued exposure.
• Rarely, allergic reactions can progress to fatal,
  anaphylactic reactions (fall in blood pressure).

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Allergy vs. Irritation

• Allergies specifically refer to clinical
  reactions resulting from the interaction of
  antigens (allergens) and antibodies.
• Allergies will affect only a portion of a given
  population.
• The sensitized workers may have symptoms at
  very low concentrations while non-sensitized
  workers will have no symptoms even at very high
  concentrations.

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Allergy vs. Irritant

• Irritants are substances which will cause
  symptoms in all individuals, though the dose
  resulting in symptoms will vary from one
  individual to the next.
• Examples include ammonia, acids/bases, chlorine,
  some organic solvents, etc.
• Irritant dermatitis looks similar to eczema
  (red, scaly, bumpy eruption)

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Asthma vs. RADS

• Reactive airway dysfunction syndrome is a form
  of reactive airway disease similar to asthma, but
  caused by irritant exposures rather than allergic
  exposures (no immunologic mechanism).
• RADS can develop after a single massive irritant
  exposure or more chronic low level exposures.

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Cacosmia

• The memory or hallucination of a foul odor.
• Refers to individuals who have medical symptoms
  in response to olfactory stimuli.

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Psychosomatic Illness

• The development of medical signs and symptoms
  (often objective) in response to psychiatric
  stress.
• Examples include hives from anxiety, irritable
  bowel syndrome triggered by anxiety, etc.

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Malingering

• Faking medical symptoms for secondary gain

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Overview of Occupational Allergies
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Types of Occupational AllergensHigh Molecular
Weight Substances

• Animal Proteins
• Mammalian mouse, rat, guinea, dogs, cats, etc.
• Insects cockroaches, bees, mites, etc.
• Molluscs crabs, shrimp
• Birds pigeons, chickens, etc.
• Fish

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High Molecular Weight substances

• Plant proteins
• Flour
• Latex
• Coffee
• Cotton dust
• Pollen
• Tobacco
• Tea
• Western red cedar

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High Molecular Weight substances

• Enzymes
• Trypsin/chymotrypsin
• Pepsin
• Pancreatic extracts
• Papain
• Amylases and proteases

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Low Molecular Weight substances

• Metals Nickel, platinum, chromium, cobalt, zinc,
  aluminum, etc.
• Fluxes aminoethyl ethanolamine, colophany.
• Drugs antibiotics, anesthetics (enflurane),
  cardiovascular drugs (methyl dopa), sulfa based
  drugs, etc.

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Low Molecular Weight substances

• Diisocyanates TDI, etc. (polyurethanes
• Anhydrides phthalic anhydrides, trimellitic
  anhydrides, etc. (epoxy resins)
• Dyes
• Wood Dust
• AldehydesFormaldehyde, glutaraldehyde, etc.

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Low Molecular Weight

• LMW substances usually cause allergic reactions
  by attaching to a larger molecule or particle
  either in the environment or in vivo this is
  called a hapten

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Case Summary

• 24 yo female hired 4/98 as research assistant.
  Her job involved procedures on mice in lab where
  other scientists also brought animals for
  necropsy on open benches. PMH significant for
  history of environmental allergies, latex
  allergy.
• 5/99, developed eye redness, scratchy throat,
  sneezing, and cough after work with mice (only
  PPE was nitrile gloves, labcoat).

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Case Summary, cont.

• PFTs
• FVC FEV1 PEF
• Baseline 5.24 4.30 6.52
• End of shift 4.18 3.27 4.32
• 2 weeks after
• no mouse work
• (end of shift) 5.01 4.36 6.48

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Case Summary, cont.

• Despite the use of HEPA mask, performance of
  procedures only in a BSC, and use of Intal, she
  continued with eye redness, tight chest, and
  raspy throat whenever she entered the animal
  rooms (lab and cage areas).
• She was permanently restricted from work with
  rodents and work in the animal areas.
• Subsequently was able to d/c all meds

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LAB ANIMAL ALLERGIES

• Prevalence ranges from 11-44 depending on the
  study.
• Prevalence estimates vary primarily because of
  differing ways of defining the disease
• Objective tests vs. subjective symptom reporting
  the lowest estimates were from studies which
  relied on employer reports the highest estimates
  simply use self-reporting of symptoms (i.e. do
  you ever get a stuffy nose at work).

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Aoyama, et al, British Journal of Industrial
Medicine, 1992

• Probably the largest cross sectional study
  involving lab animal allergies
• 26 of workers exposed to mice
• 25 of workers exposed to rats
• 31 of workers exposed to guinea pigs
• 30 of workers exposed to rabbits
• 26 of workers exposed to hamsters
• 25 of workers exposed to dogs
• 30 of workers exposed to cats
• 24 of workers exposed to monkeys

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Prevalence of Asthma

• Aoyama found a 9 prevalence of asthma symptoms
  among exposed workers
• Others found a prevalence of 4-22.
• None of these studies differentiated between
  those who developed asthma as a result of their
  animal exposure versus pre-existing asthma.

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Onset of Symptoms

• Cullinan, et al, , 1994 Prospective study of new
  workers with no previous rat exposure
• Range of 30-1369 days from time of employment to
  onset of symptoms
• Mean duration of employment before symptom onset
  was
• 365 days for chest symptoms
• 214 days for nose and eye symptoms
• 335 days for skin symptoms

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Onset of Symptoms, continued

• Assuming regular exposure, in general, most who
  develop allergies will do so within 3 years of
  employment
• One third are symptomatic in the first year, 70
  within 3 years.
• About 70 of those who eventually develop asthma
  will do so within 3 years of developing initial
  allergy symptoms.

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Specific Animal Allergens

• Urine is the major source of rodent allergen
  exposure.
• Mouse
• Mus m 1 (prealbumin) Previously known as major
  urinary protein. Found primarily in urine, but
  also in dander and hair
• Mus m 2 Found mostly in hair and dander
• Albumin Found in serum

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Animal Allergens, continued

• Rats
• Rat n 1A/Rat n 1B (alpha-2 globulin) Found in
  urine, hair, and dander.
• Albumin serum

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Animal Allergens, continued

• Guinea Pig Cav p 1 and Cav p 2, found in hair,
  dander, and urine.
• Rabbit Ory c 1 in hair, dander, and saliva and
  Ory c 2, found in hair, dander, and urine.
• Cat Fel d 1 in hair, dander, and saliva and
  albumin in serum.
• Dog Can f 1 in hair, dander, and saliva and
  albumin in serum.

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Diagnosis

• Temporal relationship of the development of
  symptoms to work with lab animals
• Across shift changes in FEV1 or PEF while working
  with lab animals (if asthma is present).
• Skin testing to specific animal proteins
• Radioallergosorbent tests (RAST) Measures the
  amount of IgE specific to a particular protein.

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Risk Factors for the Development of Lab Animal
Allergies

• History of Atopy Genetic predisposition to
  allergic conditions.
• History of cat or dog allergy
• Job title/job tasks
• Positive skin tests and/or RAST test.
• Total IgE levels

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Children of Workers Exposed to Lab Animals
Positive Skin Tests(Krakowiak, et al, 1999)
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Preventive Strategies

• Engineering Controls
• Increase ventilation and install HEPA system
• HEPA ventilated cage racks and filter top cages
• Direct airflow away from workers and toward back
  of cages (consider laminar flow ventilation)
• Increase humidity in animal areas
• Use of low dust bedding and less allergenic
  animals

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Preventive Strategies

• Administrative Controls
• Perform animal manipulations in ventilated hoods.
• Education and training to workers
• Decreased animal density
• Medical surveillance programs
• Job assignment for at risk workers (?)

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Preventive Strategies

• Personal Protective Equipment
• Lab coats
• Gloves
• Safety glasses or goggles
• Masks, preferably fit-tested HEPA respirators
• Restriction of street clothing

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Case Summary

• 34 year old female anesthesiologist with a
  history of asthma and multiple environmental
  allergies developed progressive worsening of her
  asthma, ultimately requiring high dose
  corticosteroids, despite switching to non-latex
  gloves for all procedures.
• When the hospital banned powdered latex gloves
  and used non-latex gloves whenever possible, she
  was able to wean off most of her asthma meds.

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Latex Allergy

• There are 2 distinct types of allergic reactions
  associated with latex products
• Systemic, Type I, IgE mediated allergy to
  naturally occurring latex proteins clinical
  manifestations include urticaria (hives), cough,
  sneezing, asthma, and rarely anaphylaxis.

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Latex Allergy

• Type IV, cell mediated contact allergy to
  accelerants used to polymerize latex clinical
  manifestations are localized itchy, bumpy rash at
  the site of contact. No systemic symptoms and no
  risk of anaphylaxis.
• Contact allergy is much more common than the
  systemic allergy

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Latex Allergy

• Prevalence of systemic, type I allergy depends on
  the population
• General population lt1
• Hospital workers 3
• Doctors 7
• Dentists 10
• OR nurses 10
• Children with spina bifida 22

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Latex Allergy

• Diagnosis
• Clinical history
• RAST testing
• Skin prick testing
• For contact allergy, patch testing

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Powdered Latex Gloves

• Corn starch in powdered gloves is not allergenic
  (but can be irritating). However, the powder can
  adsorb latex proteins which then become airborne
  and inspirable.
• Gloves must be powdered during manufacture in
  order to slide off of the mold. To make
  powder-free gloves, manufacturers must wash the
  gloves several times, thus also removing most
  residual free latex proteins (therefore, less
  allergenic).

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Case Summary

• A 45 year old female medical technician who works
  in the GI unit of a local hospital developed sore
  throat and cough whenever she entered the
  sterilization area.
• Cidex OD was used for sterilizing instruments.
  This procedure was not performed in a fume hood
  and room ventilation was fair. The MSDS states
  contains an aldehyde which may be a sensitizer

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Chemical Allergies

• Formaldehyde and Glutaraldehyde used as
  sterilants and disinfectants.
• Actually fairly weak allergens, but they also
  have significant irritant properties.
• It is difficult to distinguish between the
  irritant effects and true allergic reactions.
• Case reports of glutaraldehyde induced asthma

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Aldehydes

• Glutaraldehyde and formaldehyde can also cause
  gastrointestinal symptoms
• Nausea from odor
• Nausea/vomiting, diarrhea from direct irritant
  properties on the GI tract if ingested

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Chemical Allergies

• Ethylenediamine and hydrazine often used as
  additives to pharmaceutical products.
• Thimerasol mercury based preservative used in
  vaccines, contact lens solution, etc.
• Antibiotics neomycin, sulfa based drugs,
  penicillins, cephalosporins, etc. sensitization
  without symptoms can occur in the lab setting
  with full blown allergic reactions if
  administered later in therapeutic doses.

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Approach to the employee with symptoms suggesting
allergy

• Get a diagnosis- send them to an occ doc (dont
  just rely on the employee seeing their own doctor
  or allergist)
• Take the symptoms seriously
• Perform only focused environmental testing
• Make provisions for temporary removal of the
  worker from the area until more information can
  be obtained.

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Approach, continued

• Carefully look for all potential sources of
  allergens.
• Document unusual odors
• Gather MSDS on all chemicals used in the area
  (including cleaning solutions).
• Gather information on HVAC maintenance, source
  air, and ventilation system diagram.
• Look for evidence of water damage or history of
  flooding (possible mold growth)

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Approach, continued

• Involve HR, EHS, Occ health, supervisors.
• Determine if others are affected
• Examine all possible routes of exposure
• Be prepared to offer appropriate PPE if it is
  determined that the employee may safely work in
  the area with PPE
• Be aware of secondary gain
• Be ready for the fact that you may not ever get a
  final answer.

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Preventive Measures

• Potential sensitizing agents should be handled
  carefully use of gloves and safety glasses at a
  minimum.
• Use of powdered forms of potential sensitizers
  should be performed in BSC or use of N95 masks is
  recommended.
• Powder-free latex gloves only provide nitrile or
  vinyl alternatives
• All possible allergic reactions should be
  immediately reported.

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Case Summary

• 31 year old worker with history of asthma and
  multiple environmental allergies developed daily
  cough and wheezing when the company began using a
  commercial protease in the labs.
• The protease was initially weighed on open
  benches. Later, the process was moved to mobile
  ventilation cabinets and the labs were thoroughly
  cleaned. However, the worker still experienced
  cough and wheezing when entering the labs in
  which protease had been used.

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Case Summary

• Chemist at a local biotech company reports a 2
  year history of eye irritation, sneezing, and
  mild cough when working in her lab. Her symptoms
  have been fairly well controlled with
  non-sedating antihistamines. Her symptoms
  consistently resolve outside of the lab. She has
  had no allergy work-up.
• A tour of the lab reveals no obvious source of
  sensitizers, though there were anecdotal reports
  of past flooding in the lab.

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Case Summary

• Researcher with a history of lab mice allergies
  developed cough, wheezing, and laryngitis which
  was only partially controlled by oral and inhaled
  steroids. Her symptoms abated when she was away
  from work for 2 or more days and returned within
  hours of coming to work. A RAST test for MUP was
  negative.

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Case Summary, cont.

• She had worked in a second floor office in an
  administrative area for 1 1/2 years without
  difficulty. The onset of her symptoms coincided
  with the opening of a new animal lab (mice and
  rats) on the first floor under her office.

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Case Summary

• 35 year old molecular biologist developed
  symptoms of throat tightening after cleaning some
  heavy mold growth in his kitchen at home. His
  symptoms then began to recur with exposure to a
  variety of things including certain detergents
  and MacIntosh laptop computers. He even had the
  symptoms when meeting with his boss or
  co-workers, and therefore could not come to work.

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Case Summary, cont.

• Allergy work-ups were negative except positive
  mold skin testing. He had to move out of his
  apartment and stay out of work.
• Ultimately, his symptoms began to abate and he
  was able to return to work in a different office
  and he limited his exposure to co-workers
  (teleconferenced meetings, etc.).

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Questions, comments, etc.??