Lecture 12 - Infant and Child Allergies Flashcards

1
Q

what is a allergy

A

when a person reacts to a substance in the environment that are harmless to most people

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2
Q

1 in how many people will develop allergies at some time during their life

A

1 in 5 people

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3
Q

1 in how many people will develop eczema during their life

A

1 in 10

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4
Q

what % of children have a food allergy

A

5-10%

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5
Q

what % of adults have a food allergy

A

2-4%

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6
Q

allergies can occur across the lifetime but

A

many develop when we are young

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7
Q

we are less likely to grow out of an allergy if

A

it develops later in life

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8
Q

what is atopic disease

A

a genetic tendency to develop allergic disease

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9
Q

a child / person with atopic disease produces

A

elevated IgE antibodies after exposure to environmental allergens

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10
Q

atopic diseases present with one or more of …

A

asthma, allergic rhinitis and eczema or hives

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11
Q

what is atopic dermatitis (ezcema)

A

inflammation of the skin - reddened, swollen, itchy, weeping skin

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12
Q

what is asthma

A

an allergic inflammation of the bronchial airways producing swelling, narrowing and mucus = leads to difficulty breathing

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13
Q

what is allergic rhinitis

A

also known as hay fever, is a type of inflammation in the nose which occurs when the immune system overreacts to allergens in the air

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14
Q

what is a food allergy

A

an immune mediated hypersensitivity reaction to a food

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15
Q

what is hive (urtucarua)

A

itchy, raised lumps on the skin, can occur anywhere on the body

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16
Q

what is generally the first atopic disease to occur

A

ezcema

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17
Q

up to what % of children with eczema have a progression to asthma and or rhino-conjunctivitis

A

up to 40%

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18
Q

what is atopic march

A

meaning if an individual develops eczema they will be more susceptible to developing asthma of food allergies

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19
Q

what % of infants with ezcema will develop a food allergy

A

40% will also develop food allergy

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20
Q

majority of children with asthma will develop symptoms by age

A

6 and many even develop symptoms by age 3

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21
Q

what is wheezing

A

a sign of asthma, high pitched, whistling noise that occurs naturally with exhaling

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22
Q

do all children who wheeze develop asthma

A

not all children who have wheezing develop asthma and not all children who have asthma wheeze

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23
Q

what is a immune mediated response

A

can either be IgE or non IgE mediated, but involves the immune system

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24
Q

what is IgE mediated response

A

involves antibodies, picked up with a skin prick test

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25
Q

what is a non IgE mediated response

A

immune response - centered usually in the gut less immediate, does not produce antibodies

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26
Q

what happens in IgE mediated food allergy

A

Immunoglobulin E antibody identifies food proteins and signals the immune system to react

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27
Q

what are mast cells

A

first line of defence

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28
Q

where are mast cells found

A

skin, lungs, nose, mouth, gut and blood

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29
Q

what do mast cells contain

A

contain histamines which are released and increase blood flow and cause inflammation

30
Q

a food allergen is always a

A

protein

31
Q

how many foods are responsible for 90% of allergic reactions to foods and what are they

A

9

  • milk
  • eggs
  • fish
  • shellfish
  • tree nuts
  • peanuts
  • wheat
  • soybeans
  • sesame
32
Q

what are the mild to moderate symptoms of a food allergy

A
  • swelling of the face, lips or eyes
  • hives or red welts on the skin
  • red, watery eyes
  • itchy mouth or throat
  • vomiting
  • diarrhoea
33
Q

what are the severe symptoms of allergy (signs of anaphylaxis)

A
  • difficulty breathing
  • tongue swelling
  • coughing, wheezing and shortness of breath
  • baby becomes pale and floppy
34
Q

what allergies are most likely to be outgrown

A
  • cows milk (by around 5 years)
  • egg (by around 5 years)
  • wheat
  • soy
35
Q

which allergies are most likely present

A
  • peanut
  • treenut
  • fish, shellfish
36
Q

what % of infants with peanut allergy will have persistent allergy

A

approx 75%

37
Q

what are non immune mediated reactions more commonly known as

A

food intolerances

38
Q

do non immune mediated responses produce IgE antibodies after exposure

A

no

39
Q

non immune mediated reactions include reactions to

A

non protein substances such as carbohydrates, chemicals, food additives, toxins and irritants

40
Q

non immune mediated reactions are usually less

A

less immediate / delayed reaction up to 20 hours after a food is eaten

41
Q

how is diagnosis of a non immune mediated reaction usually done

A

typically elimination and reintroduction

42
Q

allergy testing is not used as

A

a screening tool because there can be false positives and this would result in exclusion of foods that would not be necessary to

43
Q

what is a skin prick test

A

drop of the allergen is put over the top of a prick or scratch of the skin, positive is a weal is larger than 3mm

44
Q

serum specific IgE blood tests measure the levels of

A

allergy antibody, or IgE produced when your blood is mixed with a series of allergens

45
Q

what is a EAST test

A

Enzyme Allergosorbent Test (serum specific IgE blood test)

46
Q

what is a RAST test

A

radio allergosorbent test (serum specific IgE blood test)

47
Q

what is the scale of serum specific IgE blood test

A

0-6, where 6 is very high and 0 is not detected

47
Q

what are the unorthodox testing methods (not supported in NZ)

A
  • cytotoxic food testing
  • vega testing
  • kinesiology
  • iridology
  • pulse testing
  • hair analysis
48
Q

what is meant by unorthodox testing for allergies

A

these tests have no scientific basis, are unreliable and provide non reproducible results, there are high prevalence of false positives

49
Q

adverse consequences of unorthadox testing methods

A
  • false positives
  • expensive
  • result in unnecessary dietary avoidance, can lead to malnutrition in children
50
Q

what are the possible explanations to the global rise in food allergies

A
  • genetics and the environment
  • hygiene hypothesis (less exposure to infection in early life)
  • development of allergy to foods by skin exposure
  • methods of food processing
  • delayed introduction of allergenic foods
51
Q

genetic influence of atopic disease is considered to be likely …..

A

multifactorial with offspring inheriting ‘atpoy genes’

52
Q

if both parents are affected by an atopic disease what % of the offspring are likely to be affected

A

40% of the offspring are affected

53
Q

how can environmental factors link to atopy disease

A

migration differences, low to high atopy country

54
Q

what does hygiene hypothesis suggest

A

suggests that reduced exposure to infectious diseases and microbial products associated with a cleaner lifestyle has suppressed the natural development of the immune system

55
Q

children become protected from allergens by eating the food …

A

early

56
Q

children become allergic by

A

by skin exposure, in the absence of the protective oral exposure

57
Q

what is dual allergen exposure hypothesis

A

skin and oral exposure to the food

58
Q

the American Academy of Paediatrics (AAP) 2008 suggest what about the maternal diet in pregnancy and food allergies

A

no protective effect of maternal exclusion of common allergen foods during pregnancy on the development of atopic disease in infants

59
Q

recent suggestions are what of the maternal diet and allergen foods during pregnancy

A

suggestion that the presence of maternal dietary proteins in amniotic fluid, cord blood and human milk might support the induction of tolerance towards solid foods in infants

60
Q

what is the recommendation of the maternal diet and allergen foods during breastfeeding

A

exclusion of common allergen foods from the maternal diet is not recommended, as this has not been shown to prevent allergies

61
Q

what is found with pregnancy and breastfeeding with a possible role in allergy prevention

A

up to 3 serves of oily fish per week may be beneficial, some evidence that omega 3 fatty acids during pregnancy and breastfeeding may help prevent eczema in early

62
Q

there is moderate evidence about what during pregnancy and breastfeeding to help prevent eczema, this is controversial

A

moderate evidence that probiotics during pregnancy and breastfeeding may hlep prevent eczema in early life = controversial

63
Q

if breastfeeding is not possible, what can be given and what is the evidence of soy or goats milk formula reducing allergies

A

a cows milk formula could be given if breastfeeding is not possible

there is no evidence that soy or goats milk formula reduces the risk of allergies compared to cows milk formula

64
Q

what is the evidence for a protective role for partially or fully hydrolysed formulas for prevention of eczema, food allergy, asthma or allergic rhinitis

A

there is no evidence to support this

65
Q

what beverages are not recommended for infants as the main source of milk before 12 months of age

A

regular cows milk, goats milk, soy milk, nut and cereal beverages are not recommended

66
Q

common food allergens (including peanut) should be introduced in age appropriate form before when

A

before 12 months of age, including high risk infants

67
Q

new common allergen foods should be introduced how

A

one at a time, around 1 or 2 days apart to detect problem foods

68
Q

once a common allergen food is tolerated, what should happen

A

continue to regularly as part of a varied diet

69
Q

what are the recommendations of skin treatment for infants

A

use skincare products that do not contain food protein