1. Asthma and Allergy  Atopy v Allergy  Asthma Aeroallergens – indoor & outdoor Aeroallergens – indoor & outdoor  Occupational allergens

2. Atopy  The propensity to produce IgE to allergens  Demonstrated using Skin prick tests to common inhalant allergens

3. Allergen-Antibody interaction

4. Prick Test Reagents

5. Skin Prick Tests

7. Allergy  IgE mediated inflammatory tissue damage in response to an allergen causing clinical disease

8. Asthma - epidemiology  X 2- 3 increase last 30 years  Concomitant similar increase in atopy, hayfever and eczema  ? Environmental Change  ? Less infections ( hygiene hypothesis )

9. Allergens  Outdoor  Pollens- –Tree –Grass  Moulds- –Alternaria –Aspergillus –Cladosporium –Penicillium

10. Allergens  Indoor –Cat –Dog –Cockroach –Birds

11. 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

12. Pollenosis and BHR

13. Allergic history and negative skin tests  Remember grass pollen allergy

14. 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

15. Why study pollens  Potential for immunotherapy

16. Indoor allergens-avoidance  House dust mite allergen –Large –Not easily air-borne –Needs close proximity to bedding to be inhaled

17. House dust mite avoidance  Mite impermeable mattress covers  Hot wash bedding linen ( 55 C )  Remove moquettes  Light curtains  Vacuum clean with high filtration cleaner

18. Mattress Covers

19. Vacuum cleaners

20. Pet allergens  Remove the pet  Clean it  Remove carpets ( x 100 fold antigen)

21. Cat Eviction

22. Asthma- none of usual aeroallergens Think of occupational asthma

23. Occupational Asthma  Asthma initiated by an agent inhaled at work  Cf. Work-related asthma – Pre-existing asthma provoked by an irritant in the workplace

24. 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

25. 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

26. Occupational Asthma

27. Serial Peak Flow- latex

28. Bronchial Provocation Testing

29. Inhalation Challenge

31. Occupational Asthma

32. Occupational asthma  Diagnosis will have major impact on patient’s life  False + ve : needless loss of job  False – ve : Needless continuing exposure  Be careful

33. Thank You  Discussion