Latex allergy

1. Latex allergy Jay E. Slater, MD CBER/OVRR/DBPAP Laboratory of Immunobiochemistry

2. Symptoms of latex allergy • Urticaria • Rhino-conjunctivitis • Wheezing • Anaphylaxis • A systemic, multisystem allergic reaction that may include any and all of the above, plus hypotension

3. Other types of latex allergy • Contact urticaria • Contact dermatitis • Irritant dermatitis

4. IgE-mediated responses

5. Mast cells

6. Initial reports • Germany, 1930’s • Europe, 1980’s • US/Canada, 1989

7. Items that elicit latex allergic responses • gloves • condoms • catheters • cofferdams • surgical drains • latex stoppers • adhesives • other

8. 7 March 1994

9. Risk groups • Meningomyelocele • Urogenital abnormalities • Health care workers • Rubber industry workers

10. Why latex? http://www.bio.ilstu.edu/armstrong/syllabi/rubber/rubber.htm

11. Why latex? From D’Auzac et al, Physiology of rubber tree latex, CRC Press, Boca Raton, 1989, p. 6

13. Latex gloves are “dipped” products

14. Hev b 1 (REF) Hev b 2 (-1,3-glucanase) Hev b 3 (microhelix component) Hev b 4 Hev b 5 Hev b 6 (prohevein) Hev b 7 (patatin analogue) Hev b 8 (profilin) Hev b 9 (enolase) Hev b 10 (Mn-superoxide dismutase) Hev b 11 (class 1 chitinase Hev b 12 (lipid transfer protein) Hev b 13 (esterase) Hevea latex antigens

15. Glove powder adsorbs and disseminated latex protein allergens Giercksky, Eur J Surg 1997; suppl 579:11-14 Green, Eur J Surg 1997; suppl 579:39-40

16. Diagnosis of latex allergy • History • Events • Risk factors • Latex-specific IgE • skin test • serum • Intervention (challenge and/or avoidance)

17. Prevalence of latex allergy • Questionnaire • Latex-specific IgE • skin test • serum • Predictive value is questionable

18. Skin tests • none licensed in US • Outside the US: • Western Allergy Services (Canada) • Stallergenes S.A. (France) • Lofarma (Italy) • ALK Abello (Denmark)

19. Serum specific IgE tests • Available tests (Hamilton, JACI 2002; 110(2 suppl):S47-S56) : • Pharmacia CAP (sens 70-80%, spec >90%) • Hycor HyTECH (sens 70-80%, spec >90%) • DPC AlaSTAT (sens 90%, spec 70%) • Specific allergens important • Adding Hev b 5 to CAP increases sensitivity by 1-2% (Lundberg, Allergy 2001; 56:794-795) • Hev b 2 + 3 + 7 is 100% sensitive for spina bifida (Kurup Clin Exp Allergy 2000; 30:359-369)

20. General population • Seroprevalence • Reinheimer (1995): 12% • Garabrant (2001) : 8-37% • Grzybowski (2002): 8% • Skin tests • Buckland (2002): 5% • Jensen (2002): 9%

21. Health care worker data • Multiple initial estimates: 5-10% • Workers compensation claim data: not a significant cause of work-associated disability (Horowitz et al. 2000-2002) • NHANES II : modest increased risk (OR up to 2.53 (1988-1991)

22. Health care workers –incidence data • 769 apprentices • dental, animal care, pastry-making • Skin tests (for latex and program-specific allergens) and questionnaire • <44 month follow-up • Incidence of latex allergy • Dental: 2.5%/year • Animal: 0.4%/year • Pastry: 1.6%/year Garabrant et al. 2001

23. Urogenital abnormalities • Spina bifida <37% • bladder exstrophy, cerebral palsy, and spinal cord injury • spina bifida, atopy, and the number of surgical interventions are independent risk factors (OR 6.76, 3.37 and 1.14/operation) (Hochleitner, et al. 2001)

27. Modes of treatment • 1. Avoidance • 2. Avoidance • 3. Avoidance • 4. Other

28. Avoidance is hard because • latex is ubiquitous in the health care environment • labeling has been erratic • threshold doses (for sensitization and reactivity) are unknown • cross-reactivity with foods

29. Cross-reactivity • banana • chestnut • avocado • other fruits

30. Hev b 3 : red kidney bean Hev b 5 : kiwi Hev b 6 : wheat germ agglutinin Hev b 7 : potato Hev b 8 : profilins Hev b 9 : fungal enolases Hev b 10 : fungal superoxide dismutases lysozymes: ubiquitous Cross-reactivity of Hevea latex antigens

31. Other approaches • better methods of prevention • premedication regimens • immunotherapy • classical • peptide based • naked DNA

32. Premedication • H1 antagonist • (H2 antagonist) • glucocorticoid • (sympathomimetic)

33. Premedication • Plausible efficacy, but • No evidence that it works • Anecdotal reports of failure • May lead to breach of latex precautions

34. Final points… • At this time, prevention is the only effective treatment for latex allergy. • Latex allergens are ubiquitous, but • Gloves are the most important source of latex allergen in the health care environment. Deal with the gloves first. Catheters are also important. • All latex allergy tests, whether RAST, ELISA, skin tests or challenges, are only as good as the allergens that are used. The allergens must be intact, and all significant specific allergens must be represented in the allergen mix used.

35. Final points… • Testing is readily available now. The predictive value of testing as a diagnostic tool is excellent. However, the value of such tests as a screening tool is uncertain. • Premedication does not prevent antigen-induced anaphylaxis. • Consider food allergy. • There is probably no way to construct a latex-free environment in the healthcare setting, but it is certainly possible to construct a latex-safe environment.

36. Final points… • All latex avoidance measures come with a price (money, resources, risk of contamination, diminished barrier protection). Latex avoidance should be consonant with the risk. • History alone is a poor predictor of latex allergy, but the predictive value of not obtaining a history is zero. Asking your patients if they have symptoms consistent with latex allergy is simple and quick, and should be part of routine screening for all medical and dental practitioners.