Asthma and allergy
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Asthma and Allergy. Atopy v Allergy Asthma Aeroallergens – indoor & outdoor Occupational allergens. Atopy. The propensity to produce IgE to allergens Demonstrated using Skin prick tests to common inhalant allergens. Allergen-Antibody interaction. Prick Test Reagents. Skin Prick Tests.

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Asthma and Allergy

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Asthma and allergy

Asthma and Allergy

  • Atopy v Allergy

  • Asthma

  • Aeroallergens – indoor & outdoor

  • Occupational allergens


Atopy

Atopy

  • The propensity to produce IgE to allergens

  • Demonstrated using Skin prick tests to common inhalant allergens


Allergen antibody interaction

Allergen-Antibody interaction


Prick test reagents

Prick Test Reagents


Skin prick tests

Skin Prick Tests


Allergy

Allergy

  • IgE mediated inflammatory tissue damage in response to an allergen causing clinical disease


Asthma epidemiology

Asthma - epidemiology

  • X 2- 3 increase last 30 years

  • Concomitant similar increase in atopy, hayfever and eczema

  • ? Environmental Change

  • ? Less infections ( hygiene hypothesis )


Allergens

Allergens

  • Outdoor

  • Pollens-

    • Tree

    • Grass

  • Moulds-

    • Alternaria

    • Aspergillus

    • Cladosporium

    • Penicillium


Allergens1

Allergens

  • Indoor

    • Cat

    • Dog

    • Cockroach

    • Birds


Inhalation of allergen

Inhalation of allergen

  • Immediate response ( IgE mediated )

    • Max: 20 min.

    • Ends : 60 min.

  • Late response in 50% (Eosinophil )

    • Onset 3h

    • Max 12 h

    • End 24 h

  • Responsible for airways hyperreactivity

  • Allergen ID and avoidance therefore very important


Pollenosis and bhr

Pollenosis and BHR


Allergic history and negative skin tests

Allergic history and negative skin tests

  • Remember grass pollen allergy


Pollenosis

Pollenosis

  • Prof. Paul Potter, Cape Town

  • Big role for grass pollens in respiratory allergy

  • Kikuyu grass

  • Bermuda grass

  • Buffalo grass ( l’herbe bourrique )

  • SPT regents to detect allergy to these being developed

  • Mauritus has all of these grasses in abundance


Why study pollens

Why study pollens

  • Potential for immunotherapy


Indoor allergens avoidance

Indoor allergens-avoidance

  • House dust mite allergen

    • Large

    • Not easily air-borne

    • Needs close proximity to bedding to be inhaled


House dust mite avoidance

House dust mite avoidance

  • Mite impermeable mattress covers

  • Hot wash bedding linen ( 55 C )

  • Remove moquettes

  • Light curtains

  • Vacuum clean with high filtration cleaner


Mattress covers

Mattress Covers


Vacuum cleaners

Vacuum cleaners


Pet allergens

Pet allergens

  • Remove the pet

  • Clean it

  • Remove carpets ( x 100 fold antigen)


Cat eviction

Cat Eviction


Asthma none of usual aeroallergens

Asthma- none of usual aeroallergens

Think of occupational asthma


Occupational asthma

Occupational Asthma

  • Asthma initiatedby an agent inhaled at work

  • Cf. Work-related asthma

    • Pre-existing asthma provoked by an irritant in the workplace


Occupational asthma1

Occupational asthma

  • Only a % of workers affected

  • Latent period before onset ( 2 Yr.)

  • Improvement during periods away from work

  • Once established can be triggered by really small doses of antigen


Usual suspects

HMW ( Biologic )

Latex

Flour ( 334 )

Laboratory mammals(188)

Bacillus subtilis

LMW ( haptens )

Colophony ( 175 )

Wood dust

Diisocyanates ( 658 )

Platinum salts

Acid anhydrides ( 364 )

Glutaraldehyde

Plastics workers

Bone cement

Usual suspects


Occupational asthma2

Occupational Asthma


Serial peak flow latex

Serial Peak Flow- latex


Bronchial provocation testing

Bronchial Provocation Testing


Inhalation challenge

Inhalation Challenge


Inhalation challenge1

Inhalation Challenge


Occupational asthma3

Occupational Asthma


Occupational asthma4

Occupational asthma

  • Diagnosis will have major impact on patient’s life

  • False + ve : needless loss of job

  • False – ve : Needless continuing exposure

  • Be careful


Thank you

Thank You

  • Discussion


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