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The spectrum of allergic diseases. Hugo Van Bever Department of Pediatrics National University Singapore. APAPARI workshop – Hanoi, Vietnam – May 2008. APAPARI - Education. 1. Joint meetings with Allergy Societies - 2002: Japan (Tokyo) - 2003:Singapore (workshop) - PowerPoint PPT Presentation
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The spectrum of allergic diseases
Hugo Van BeverDepartment of Pediatrics
National University Singapore
APAPARI workshop – Hanoi, Vietnam – May 2008
APAPARI - Education 1. Joint meetings with Allergy Societies
- 2002: Japan (Tokyo)- 2003:Singapore (workshop)- 2004: Hong Kong (IPRAIC)- 2005: S-Korea (Seoul)- 2006: Indonesia (Jakarta)- 2007: Philippines (Manila) & WAO (Bangkok)- 2008: Singapore (SPS – Oct 2008)
2. Training courses on pediatric allergy- 2006: Jakarta (Indonesia) / Balikpapan (Borneo)- 2007: Phom Penh (Cambodia) / Jakarta / Ho Chi Minh (Vietnam)- 2008: Hanoi (Vietnam)
Vietnamese studies on paediatric allergy
- ISAAC-based asthma and atopic symptoms among Hanoi school children. Nga NN et al. Pediatr Allergy Immunol 2003, 14, 272-9.
- Obesity is associated with increased risk of allergy in Vietnamese adolescents. Irei V et al. Eur J Clin Nutr 2005, 59, 571-7.
- Poor sanitation and helminth infection protect against skin sensitization in Vietnamese children: a cross-sectional study. Flohr C, et val. J Allergy Clin Immunol 2006, 118, 1305 – 11.
- Prevalence of asthma and asthma-like symptoms in Dalat Highlands, Vietnam. Sing Med J 2007, 48, 294 – 303.
ISAAC-based asthma and atopic symptoms among Hanoi school children. Nga NN et al. Pediatr Allergy
Immunol 2003, 14, 272-9.
- Hanoi
-cross-sectional study
-5 -11 year-old
-Response rate 66.4%
- 969 responders
Cumulative prevalence of asthma, rhinitis and eczema in Singaporean children.
1 - 2 yrs-old2002 -2003
4 - 6 yrs-old2000
6 – 7 yrs-old2001
12 – 15 yr-old2001
Increase in prevalence of allergic diseases
- asthma
- rhinitis
- eczemaInduction of the expression of allergy
changes in the environment
Allergy = a feature and NOT a disease !
= … the ability to produce specific antibodies (IgE) to different substances of the
environment (inhalant and food allergens)…
IgE inflammation
shock organs symptoms
= swelling - narrowing
Allergic diseases …
ALLERGYALLERGY
healthy asthma
rhinitisconjunctivitis
enteritis
migraine
urticaria
eczema
Positive skin tests in 273 HEALTHY children at the age 6-7 years (Belgium - 1996).
ALLERGEN n %
- HDM 21 8 %
- Cat dander 6 2 %
- Birch pollen 1 0 %
- Grass pollen 8 3 %
- ANY 29 11 %
Environmental substances = allergens (proteins…)
1. Inhalant allergens house dust mites, pollen pets, moulds
2. Food allergens egg, cow’s milk, soy, wheat ( < 3 yrs) peanuts, fish, shrimp, etc… (> 3 yrs)
Contact with food allergens
eating – drinking
touching
smelling
breast milk - prenatal
Food allergens in house dust.
Witteman AM, van Leeuwen J, van der Zee J, Aalberse RC. Int Arch Allergy Immunol. 1995 Aug;107(4):566-8.
ovomucoid -lactoglobulin
microgr/g dust
10
1
0.1
0.01
The amount of ovomucoid and -lactoglobulin in 11 house dust samples
0.073 microg/g dust = detection limit ovomucoid0.016 microg/g dust = detection limit lactoglobulin
“ Kiss of death “
5% of adults with food allergy
Foods: peanuts, nuts, apple, pea, fish
Relationship: husband, boyfriend, etc.
Hallett et al, NEJM 2002, 346, 1833
House Dust Mites in Singapore
• High temp and humidity provides perfect environment for HDMs
• High counts (> 100 mites/g dust) of HDM are isolated in Singapore
• A wide variety of mite species is isolated other than Dermatophagoides.
• Blomia tropicalis is predominant.
Mite Species Present in Singaporean Mattresses
Species % (n = 50)B. tropicalis 94D. pteronyssinus 80S .brasiliensis 84T. granarius 44D. farinae 26A. malaysiensis 20C. malaccensis 24M. intermedius 12
Chew FT 1999 Clin Exp Allergy 29:201-206
Allergic diseases
1. GENETIC CONSTITUTION
2. ENVIRONMENT - Prenatal (pregnancy) - Postnatal (first months of life)
Genetic constitution
Parents Risk
1. both are negative 18 % 2. mother negative – father positive 40 % 3. mother positive – father negative 50 % 4. both positive 70 % 5. both strongly positive 90 %
Allergic diseases
1. GENETIC CONSTITUTION
2. ENVIRONMENT - Prenatal (pregnancy) - Postnatal (first months of life)
Direction of immune responses in early life
Birth
Non-allergic (Th1)
Allergic (Th2)allergic profile (Th2 predominance)
Factors
1. constitution 2. bacterial load
3. allergen exposure
ATOPY = inbalance
Th3
Th1
Th2
regulatory T cellsIL-10, TGF-b
Postnatal immune deviation from allergic (Th2) to non-allergic (Th1)
POSITIVE 1. Increased bacterial load
- family size, farming- day care attendance- probiotics (Lactobacillus sp.) prebiotics, etc.
2. Tolerance through high exposure to allergens (pets – other allergens)
NEGATIVE 1.House dust mite – pollen (low doses) 2. RSV 3. Pollution (DEPs – cigarette) 4. Antibiotics - paracetamol
Diagnosis of allergy 1. History 2. Clinical examination
3. SPT = golden standard !
4. Specific IgE 5. Other lab tests: ECP, cytokines, etc… 6. eNO
7. Allergen provocation test (nasal, bronchial, etc…)
Unproven diagnostic tests for allergy…
- IgG against everything you can dream
- Electrodermal tests (“ Bioreasonance tests “)
- Other “witchcraft” (“ Kinesiology ”)
Skin prick testing
= golden standard for diagnosing allergy in children & adults