apapari training courseapapari.org/download/news/cambodia allergy in young...
TRANSCRIPT
![Page 1: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/1.jpg)
Allergy in young childrenAllergy in young children
Hugo Van BeverNational University
Singapore
Phnom Penh, 26 May 2007
APAPARI TRAINING COURSE
![Page 2: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/2.jpg)
APAPARI 2005 Seoul, S-Korea
![Page 3: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/3.jpg)
APAPARI –
JACIN MEETING, JAKARTA –
APRIL 2006
![Page 4: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/4.jpg)
APAPARI -
Education1. Joint meetings with National Allergy Societies
-
2002: Japan (Tokyo)-
2003:Singapore (workshop)-
2004: Hong Kong (IPRAIC)-
2005: S-Korea (Seoul)-
2006: Indonesia (Jakarta)-
2007: Philippines (Manila) & WAO (Bangkok)
2. Training courses on pediatric allergy-
2006: Indonesia (Jakarta) / Borneo-
2007: Cambodia / Jakarta / Vietnam
![Page 5: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/5.jpg)
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
![Page 6: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/6.jpg)
Allergic diseases Allergic diseases ……
ALLERGY
healthy asthma
rhinitis conjunctivitis
enteritis
migraine
urticaria
eczema
![Page 7: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/7.jpg)
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 %
![Page 8: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/8.jpg)
Allergy, one feature with many faces
SKIN
AIRWAYS
![Page 9: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/9.jpg)
Allergy: Allergy: ……
mild to severemild to severe
![Page 10: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/10.jpg)
“
The Allergic March “
![Page 11: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/11.jpg)
The Allergic March
1. Intestinal symptoms
2. Eczema
3. Asthma
4. Hay fever
0 -
3 months
1 yr
1 -
6 months
7 yr
1 -
3 yr
14 yr
4 -
7 yr
40 yr
START
STOP
![Page 12: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/12.jpg)
Environmental substances = allergens (proteins…)
1. Inhalant allergenshouse dust mites, pollenpets, moulds
2. Food allergensegg, cow’s milk, soy, wheat ( < 3 yrs)peanuts, fish, shrimp (> 3 yrs)
![Page 13: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/13.jpg)
House Dust MitesHouse Dust Mites
Blomia tropicalis Dermatophagoides farinae
![Page 14: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/14.jpg)
AsthmaRhinitisEczema
![Page 15: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/15.jpg)
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.
![Page 16: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/16.jpg)
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 12Chew FT 1999 Clin Exp Allergy 29:201-206
![Page 17: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/17.jpg)
The increase of allergic diseases.
1960 1980
1990 2000
?
![Page 18: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/18.jpg)
Inverse relation between the incidence of Inverse relation between the incidence of infectious diseases and immune disordersinfectious diseases and immune disorders
(Bach JF, NEJM 2002, 347, 911)(Bach JF, NEJM 2002, 347, 911)
![Page 19: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/19.jpg)
Increasing hospital admissions for systemic allergic disorders in England: analysis of national admissions data
Br Med J, 2003, 327:1142-1143.
![Page 20: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/20.jpg)
Direction of immune responses in early life
Birth
Non-allergic
Allergicallergic profile
Factors1. constitution
2. bacterial load3. allergen exposure
![Page 21: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/21.jpg)
The Th1
- Th2
immune system around birth.
Th2
priming
boosting immune deviation
BIRTH
in utero postnatal
Th2
Th1
Allergen exposure -Bacterial load +
Genetics
placenta
![Page 22: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/22.jpg)
Hygiene hypothesis
Bacterial load vs.
allergen contacts
![Page 23: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/23.jpg)
Hygiene levels in a contemporary population cohort are associated with wheezing and atopic
eczema in
preschool children. Sheriff et al. Arch Dis
Childh
2002,87,26.
Increasing hygiene scores
-
wheezing
OR = 1.04 (95% CI: 1.00 –
1.08)-
atopic
eczema OR = 1.04 (95% CI: 1.01 –
1.07)
![Page 24: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/24.jpg)
Hygiene hypothesisHygiene hypothesis
Have bacterial load and/or antigen exposure changed since
the 80s ???
NO EVIDENCE
![Page 25: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/25.jpg)
The increase of allergic diseases.
1960 1980
1990 2000
?PARACETAMOL
BROADSPECTRUM ANTIBIOTICSALLERGEN AVOIDANCE
![Page 26: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/26.jpg)
Does usage of antibiotics increase the risk of allergy –
asthma ?
1. Farooqi et al. Early childhood infection and atopic disorder. Thorax 1998; 53: 927-32.
2. Wickens et al. Antibiotic use in early childhood and the development of asthma. Clin Exp Allergy 1999; 29: 766-71.
3. Wjst et al. Early antibiotic treatment and later asthma. Eur J Med Res 2001; 6: 236-71.
4. Droste et al. Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease? Clin Exp
Allergy 2000; 30: 1547-53.
![Page 27: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/27.jpg)
Does the use of antibiotics in early childhood increase the risk of asthma
and allergic disease?
Droste JHJ, Wieringa MH, Weyler JJ, Nelen VJ, Vermeire PA, Van Bever HP.
Clin Exper Allergy 2000, 30, 1547 –
1553.
![Page 28: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/28.jpg)
Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease?
Clin Experim Allergy 2000, 30, 1547 –
1553.
0
5
10
15
20
No parHF parHF No parHF par HF
no ABAB
%
*
*
Asthma Hay Fever* p < 0.05
![Page 29: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/29.jpg)
05
101520253035
No parHF parHF No parHF par HF
no ABAB
%*
Eczema Atopy (SPT +)* p < 0.05
Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease?
Clin Experim Allergy 2000, 30, 1547 –
1553.
![Page 30: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/30.jpg)
Parental hay fever+
Early usage of antibiotics
Increased risk for...Asthma
Hay feverEczema …
at the age of 7 –
8 yrs
Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease?
Clin Experim Allergy 2000, 30, 1547 –
1553.
![Page 31: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/31.jpg)
Antibiotica use during infancy promotes a shift in the Th1/Th2 balance toward Th2-dominant immunity in mice.
Oyama et al. J Allergy Clin Immunol 107, 153-9, 2001
total IgE
weeks
kanamycin
control
10 30
![Page 32: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/32.jpg)
ParacetamolParacetamol ……
![Page 33: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/33.jpg)
Sale of analgesics in NorwaySale of analgesics in Norway
![Page 34: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/34.jpg)
Paracetamol sales and atopic disease in children and adults: an ecological analysis.
Newson et al. Eur Respir J 16, 817-23, 2000
“
…
the possibility is raised that variation in paracetamol
usage
may explain some of the variation in atopic disease prevalence between countries…”
![Page 35: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/35.jpg)
Ped
Allergy Immunol
2007, 18, 128‐34.
Ped
Allergy Immunol
2007, 18, 128-34
![Page 36: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/36.jpg)
Risk factors Outcomes of interestOlder sibling (7-10 y.o) Asthma, allergic asthmaYoung maternal age at delivery Asthma Low allergen exposure (≤ 6 mths old) AsthmaParacetamol (≤ 6 mths old, 4-6 mths old) AsthmaParacetamol (pregnancy) Allergic asthmaLow birth weight Allergy
…
Significant and relevant results
![Page 37: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/37.jpg)
… Hypothesis
Antibiotics
Decreased bacterial load
Paracetamol
Decreased TNF-α
secretion
Decreased Th1
stimulation
![Page 38: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/38.jpg)
Primary prevention of allergy...
Allergen exposure
-
AVOID ???
- INCREASE ???How to m
easure a
llergen e
xposure?
![Page 39: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/39.jpg)
Prenatal sensitization to allergens…does it exist?
1. clinical evidence (peanuts –
ovalbumin
–
pollen –
house
dust mite –
cat -
dog)
2. allergens in amniotic fluid & cord blood
3. active transport through placenta
![Page 40: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/40.jpg)
Recent studies on prenatal allergen exposure
1. The effect of prenatal exposure on total IgE
at birth and sensitization at 12 months and 4 years: The PYAMA study. Kerkhof
et al. PAI, 2007, 16, 10.
2. Prenatal factors associated with the development of eczema in the first year of life. Kurzius-Spencer et al. PAI, 2007, 16, 19.
3. Prenatal exposure to mite and pet allergens and total serum IgE
at birth in high-risk children. Schonberger
et al. PAI, 2007, 16, 27.
![Page 41: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/41.jpg)
Recent studies on prenatal allergen exposure
1. The effect of prenatal exposure on total IgE
at birth and sensitization at 12 months and 4 years: The PYAMA study. Kerkhof
et al. PAI, 2007, 16, 10.
2. Prenatal factors associated with the development of eczema in the first year of life. Kurzius-Spencer et al. PAI, 2007, 16, 19.
3. Prenatal exposure to mite and pet allergens and total serum IgE
at birth in high-risk children. Schonberger
et al. PAI, 2007, 16, 27.
…
a short-lasting protective effect of exposure todog on total IgE
and early sensitization.
…
in utero
factors (maternal IgE, colds, eczema)increase the risk of eczema.
…prenatal exposure to HDMis associated with higher IgE
levels at birth
![Page 42: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/42.jpg)
Exposure to peanuts in utero
and in infancy and the development of sensitization to peanut
allergens in young children.
Frank L, Marian A, Visser
M, Weinberg E, Potter PC. Pediatr
Allergy Immunol
1999, 10, 27-32.
…
mothers who consumed peanuts more than once a week during pregnancy were more likely to have a peanut-allergic child than mothers who consumed peanuts less than once a week (odds ratio=3.97, 98% confidence interval 0.73-24).
![Page 43: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/43.jpg)
Detection of house-dust-mite allergen in amniotic fluid and umbilical-cord blood.
Holloway et al. Lancet 2000, 356, 1900-2.
Positive maternal blood samples (21%)
** Der
p 1-
amniotic fluid
24 / 43 ( 56 % )
-
cord blood
15 / 24 ( 63 % )
2 routes of allergen transfer-
transamniotic
- transplacental
![Page 44: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/44.jpg)
Prenatal sensitization does exist…
1. Food allergens (milk, egg, peanut)
2. Inhalant allergens (HDM, pollen, pets)
... but, allergen exposure is difficult to measure
![Page 45: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/45.jpg)
Early postnatal allergen Early postnatal allergen exposureexposure……
Pets
House dust mites
![Page 46: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/46.jpg)
Lancet 2001Non‐linear allergic response to cat allergen
contact
allergy
![Page 47: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/47.jpg)
Primary prevention of allergy by house dust mite avoidance
-
Contradictory results
-
Positive results are borderline
-
No data on HDM exposure in young children
-
Prenatal exposure has been shown.
![Page 48: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/48.jpg)
Woodcock A, Lowe LA, Murray CS, Simpson BM, Pipis SD, Kissen
P, Simpson A, Custovic
A; NAC
Manchester Asthma and Allergy Study Group.
Early life environmental control: effect on symptoms,
sensitization, and lung function at age 3 years.
Am J Respir
Crit
Care Med 2004, 170, 433-9.
…
stringent environmental control in newborns was associated with an increased risk of mite sensitization at the age of 3
years
Conclusion
![Page 49: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/49.jpg)
Impossible to avoid
![Page 50: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/50.jpg)
sensitization symptoms
allergen concentration allergen concentration
high risk zone
in sensitized subjects…
allergen avoidance
Sensitization to allergens….
IgE
![Page 51: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/51.jpg)
Attempts to avoid HDMmay result in increased sensitization…
HDM conc.
sensitization
1
2
![Page 52: APAPARI TRAINING COURSEapapari.org/download/news/CAMBODIA Allergy in young children[1]_1.pptx.pdfAllergy in young children Hugo Van Bever. National University Singapore. Phnom Penh,](https://reader030.vdocuments.site/reader030/viewer/2022040503/5e2cd8f005df5046b41b70a4/html5/thumbnails/52.jpg)
Consequences of allergen avoidanceConsequences of allergen avoidance……
1. In primary preventionresults in exposure to a low dose of
allergen = IgE
response(high dose = IgG
response -
tolerance)
2. In secondary –
tertiary prevention
(after sensitization)
results in less symptoms(cfr. dose –response curve)