Objectives and background

Objectives To identify the allergic versus the non allergic individual To understand the strengths and limitations of conventional and alternative allergy testing To select the appropriate management strategy following a relevant history and appropriate testing

Products of the mast cell Preformed - immediate release Histamine Tryptase Hydrolases Secreted mediators - released a few hours later Prostaglandins Leukotrienes Cytokines

Is allergy becoming more common? Selective perception ? Previously underestimated Increasing worldwide Incidence of hayfever and asthma rose in East Germany following unification

So why are allergies increasing? The role of the farm environment in reducing the risk of hayfever and asthma is established. Applies only to children in the first year of life and must to be maintained to aged 5. The “Farm Effect” may result from the increased exposure to bacterial products such as endotoxin

Endotoxin - LPS - from outer cell membrane of all gram negative bacteria Presence of household animals is associated with higher levels of house dust and airbourne endotoxin in metropolitan homes Paradoxically the high exposure to cat allergens  reduced sensitisation, whereas high HDM  increased likelihood of sensitisation.

Local factors will significantly alter the endotoxin exposure in the home. Personal hygiene measures such as fastidiousness of bathing, laundering and floor cleanliness are prime endotoxin reducing candidates

Prevalence of Atopic Eczema Urban > Rural Small > Large families Well off > Poorer households

Genetic influence Parental atopy especially maternal Concordance for allergy between twins

“Hygiene hypothesis” ‘Modern living is associated with too little microbial stimulation early in life’ ‘Microbial deprivation syndrome’ - cleaner environment and the widespread use of antibiotics’ Higher birth order associated with allergies, -‘The Sibling effect’ Recurrent infections lead to Th1 >>Th2 (multiple rather than a few microbial species)

Probiotics ‘Living (or inactivated) organisms that are claimed to exert when ingested beneficial effects on health’ EAACI 2002 Particularly Lactobacilli, Bifidobacteria, Enterococci and E. Coli Meningitis associated with Bifidobacteria Fatal sepsis with a vancomycin resistant Lactobacillus Only preliminary studies available and not conclusive

Probiotics in primary of atopic disease: a randomised placebo controlled trial Lactobacillus GC given 4 weeks prenatally to mothers with > one first degree relative with atopic eczema, allergic rhinitis and asthma and postnatally for 6 months to breastfeeding mothers/their infants End point - chronic recurring eczema Eczema diagnosed in 46/132 (35%) Frequency of eczema in probiotic group was half that in placebo group, 15/64 (23%) vs 31/68 (46%) The Lancet 2001; 357:1076-9, follow up 2003;361: SPT same