Allergy Flashcards

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1
Q

Define Hypersensitivity

A

Objectively reproducible signs and symptoms following exposure to a stimulus that is tolerated by most

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2
Q

Define Allergy

A

Hypersensitivity reaction initiated by specific immunological mechanisms
Can be IgE or non IgE mediated

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3
Q

Define Atopy

A

Personal and or familial tendency to produce IgE AB in response to ordinary exposures to potential allergens

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4
Q

Define Anaphylaxis

A

Serious allergic reaction with bronchial/laryngeal/CVS involvement that is rapid in onset and may cause death

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5
Q

Describe the mechanism of an IgE Mediated Allergic reaction

A

Early phase occurring within minutes of exposure caused by histamine release (eg angio-oedema, urticaria)

Late phase after 4-6 hours (Nasal Congestion)

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6
Q

Describe the mechanism of an Non IgE Mediated Allergic reaction

A

Delayed onset of symptoms and more varied course

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7
Q

What is the Hygiene Hypothesis?

A

Family Size/Parasite exposure/Infections/Antibiotics/Farming exposure all determines microbiological exposure and allergy risk

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8
Q

Describe the ‘Allergic March’

A

Eczema and food allergy develop in infancy

Allergic Rhinitis/Asthma begin in preschool

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9
Q

Describe some novel preventative theories regarding allergies

A

Probiotics during late pregnancy and lactation to prevent eczema

Early introduction of peanut/egg

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10
Q

State four things that might be seen in an allergy examination (non acute)

A

Mouth Breathing (due to nasal congestion)
Allergic Salute (rubbing an itchy nose)
Pale and Swollen inferior turbinates
Atopic Eczema

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11
Q

How can Immunotolerance be increased?

A

Solutions of allergen to which patients are allergic are given subcut/sublingually on a regular basis for 3-5 years

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12
Q

Define Food Allergy

A

Pathological immune response mounted against specific food protein

Usually IgE mediated but can be non IgE

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13
Q

Define Food Intolerance

A

Non immunological hypersensitivity to a specific food

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14
Q

Allergies can be Primary or Secondary, what is the difference?

A

Primary - Children react on first exposure (younger - milk and eggs, older - peanuts and fish)

Secondary - Cross reactivity between proteins present in fresh fruit/veg/nuts and those present in pollens (AKA Pollen Food Syndrome)

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15
Q

How does an IgE Food Allergy present?

A
  • Varies from Urticaria, to facial swelling to Angio-oedema

- Normally within 10-15 minutes of ingestion

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16
Q

Food Associated Exercise Induced allergy is a specific type of IgE allergy, how does it present?

A

Food triggers anaphylaxis but only if ingestion is followed by exercise within two hours

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17
Q

How does Non IgE food allergy present?

A

Occurs later after ingestion and tends to resolve earlier

Diarrhoea, Vomiting, Abdominal Pain, Faltering Growth

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18
Q

Food Protein Induced Enterocolitis Syndrome is a specific type of Non IgE Food Allergy, how does it present?

A

Profuse vomiting potentially leading to shock

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19
Q

How are IgE and non IgE food allergies diagnosed respectively?

A

IgE - skin prick tests, specific IgE levels in blood

Non IgE - harder to diagnose so generally reliant on clinical history and exam, can do intestinal biopsy

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20
Q

Why can you have a positive wheal on skin prick test without symptoms?

A

Sensitisation

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21
Q

How are Food Allergies managed?

A

Avoidance of known triggers (inc cross allergies)

Management plan for parents and child (mild - antihistamines, severe - epipen)

22
Q

What is the prognosis of food allergies?

A

Food allergy to Cows Milk and Egg normally resolves in childhood

Nuts and Seafood allergy persists

23
Q

What is Cows Milk Protein Allergy?

A

Immune mediated allergic response to naturally occurring milk proteins (Casein and Whey)

24
Q

CMPA can be IgE or Non IgE, and present in the classical ways. What is the different reaction pathways?

A

IgE Mediated - Type One Hypersensitivity caused by B cells producing IgE which trigger histamine and cytokine release

Non IgE Mediated - T Cell Activation

25
Q

Describe five features of an allergy focussed history

A
Atopy FH
Infants diet and feeding
Mothers diet if breast fed 
Age of onset
Which Milk/Formula
26
Q

Give three examinations that should be done on suspected CMPA

A

General GI Exam
Growth Charts
Atopic Comorbidities

27
Q

How is CMPA diagnosed?

A

Normally a clinical diagnosis

Referred for IgE if faltering growth, >1 reaction, persistent parental suspicion

28
Q

How is CMPA managed?

A

Avoidance of Cows Milk in all forms (including mothers diet if breast fed)
Reassess every 6-12m

29
Q

How is CMPA managed if they are formula fed?

A

Extensively Hydrolysed Formula (cheaper’

Amino Acid Formula (second line, more expensive)

30
Q

Why is Soya Based Formula not recommended in CMPA?

A

Weak oestrogenic effect

Phytate may inhibit mineral and element absorption

31
Q

Describe the Milk Ladder for non IgE CMPA

A

1) Cookie
2) Muffin
3) Pancake
4) Cheese
5) Yoghurt
6) Pasteurised Milk

32
Q

What is Lactose Intolerance?

A

Result of enzyme deficiency rather than IgE mediated

Rarely presents in <6 y

33
Q

What are the four types of Lactose Intolerance?

A

Primary - Autosomal recessive and develops at various ages

Secondary - following damage to intestinal mucosa

Congenital - Rare, Autosomal Recessive

Developmental - in premature babies, improves as intestine matures

34
Q

How does Lactose Intolerance present?

A

Bloating, Flatulence, Abdominal Discomfort, Loose Watery Stools

Failure to thrive

35
Q

How is Lactose Intolerance normally diagnosed?

A

Generally clinical - trial of two weeks lactose free followed by symptoms on reintroduction

36
Q

What is the ‘Lactose Tolerance Test’?

A

Dose of 2g/kg of lactose (up to 50g)

Note the blood sugar, if positive, the BGC shouldn’t rise and there should be an onset of symptoms

37
Q

What is one investigation other than the Lactose Tolerance Test that could be used to diagnose Lactose Intolerance

A

Hydrogen breath test

Hydrogen is a by product of bacterial fermentation of undigested lactose

38
Q

How is Primary Lactose Intolerance managed?

A

Avoidance of lactose to varying extents

Higher fat content is better tolerated as it slows gastric emptying

39
Q

How is Secondary Lactose Intolerance managed?

A

Fluid rescucitation may be required

40
Q

How is Developmental Lactose Intolerance managed?

A

Full lactose feeds are more likely to induce tolerance

41
Q

How is Congenital Lactose Intolerance managed?

A

Cannot breast feed

Requires lactose free formula and subsequently food

42
Q

What electrolytes may be low as a complication from Lactose Intolerance?

A

Calcium
Magnesium
Zinc

43
Q

Define Anaphylaxis

A

Severe life threatening systemic type 1 hypersensitivity reaction

44
Q

Anaphylaxis will initially be managed with an A to E assessment. What interventions are likely?

A
  • Secure airway
  • Consider Oxygen
  • IV fluid bolus
  • Lie patient flat to promote cerebral perfusion
45
Q

State the medication required in an Anaphylactic reaction (adult doses)

A

0.5ml 1:1000 Adrenaline IM

100-300mg IV Hydrocortisone

10mg IV/IM Chlorphenamine

46
Q

After the initial management, how should the child suffering anaphylaxis be treated?

A

Admit to Paediatric Ward (biphasic reaction)

Confirm by measuring serum tryptase within 6 hours

47
Q

Define Allergic Rhinitis

A

IgE mediated type 1 hypersensitivity causing an inflammatory response in the nasal mucosa

Can be seasonal, perennial or occupational

48
Q

How is Allergic Rhinitis managed?

A

Avoid the trigger (hoover and change pillows regularly, staying indoors in high pollen count)

Oral Antihistamines

Nasal Sprays (don’t sniff) (fluticasone or antihistamine)

49
Q

Give examples of the different types of antihistamine

A

Non Sedating - Cetirizine, Loratidine

Sedating - Chlorphenamine, Promethazine

50
Q

Define Urticaria

A

Itchy red blotchy rash from swelling of superficial skin (secondary to mast cell activation)

(Called Angio-oedema when it affects deeper tissues)

51
Q

Describe the appearance of Urticaria

A

Itchy white papule/plaque surrounded by erythematous flare

52
Q

How is Urticaria managed?

A
Avoid aggravating factors (overheating, stress)
Topical Antipruritics (Calamine or topical menthol)
Non sedating antihistamines (3-6 months)

If severe can give oral steroids