Allergy

Question 1

Define Hypersensitivity

Answer 1

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

Question 2

Define Allergy

Answer 2

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

Question 3

Define Atopy

Answer 3

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

Question 4

Define Anaphylaxis

Answer 4

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

Question 5

Describe the mechanism of an IgE Mediated Allergic reaction

Answer 5

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

Late phase after 4-6 hours (Nasal Congestion)

Question 6

Describe the mechanism of an Non IgE Mediated Allergic reaction

Answer 6

Delayed onset of symptoms and more varied course

Question 7

What is the Hygiene Hypothesis?

Answer 7

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

Question 8

Describe the ‘Allergic March’

Answer 8

Eczema and food allergy develop in infancy

Allergic Rhinitis/Asthma begin in preschool

Question 9

Describe some novel preventative theories regarding allergies

Answer 9

Probiotics during late pregnancy and lactation to prevent eczema

Early introduction of peanut/egg

Question 10

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

Answer 10

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

Question 11

How can Immunotolerance be increased?

Answer 11

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

Question 12

Define Food Allergy

Answer 12

Pathological immune response mounted against specific food protein

Usually IgE mediated but can be non IgE

Question 13

Define Food Intolerance

Answer 13

Non immunological hypersensitivity to a specific food

Question 14

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

Answer 14

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)

Question 15

How does an IgE Food Allergy present?

Answer 15

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

- Normally within 10-15 minutes of ingestion

Question 16

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

Answer 16

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

Question 17

How does Non IgE food allergy present?

Answer 17

Occurs later after ingestion and tends to resolve earlier

Diarrhoea, Vomiting, Abdominal Pain, Faltering Growth

Question 18

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

Answer 18

Profuse vomiting potentially leading to shock

Question 19

How are IgE and non IgE food allergies diagnosed respectively?

Answer 19

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

Question 20

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

Answer 20

Sensitisation

Question 21

How are Food Allergies managed?

Answer 21

Avoidance of known triggers (inc cross allergies)

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

Question 22

What is the prognosis of food allergies?

Answer 22

Food allergy to Cows Milk and Egg normally resolves in childhood

Nuts and Seafood allergy persists

Question 23

What is Cows Milk Protein Allergy?

Answer 23

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

Question 24

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

Answer 24

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

Non IgE Mediated - T Cell Activation

Question 25

Describe five features of an allergy focussed history

Answer 25

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

Question 26

Give three examinations that should be done on suspected CMPA

Answer 26

General GI Exam Growth Charts Atopic Comorbidities

Question 27

How is CMPA diagnosed?

Answer 27

Normally a clinical diagnosis Referred for IgE if faltering growth, >1 reaction, persistent parental suspicion

Question 28

How is CMPA managed?

Answer 28

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

Question 29

How is CMPA managed if they are formula fed?

Answer 29

Extensively Hydrolysed Formula (cheaper’ Amino Acid Formula (second line, more expensive)

Question 30

Why is Soya Based Formula not recommended in CMPA?

Answer 30

Weak oestrogenic effect Phytate may inhibit mineral and element absorption

Question 31

Describe the Milk Ladder for non IgE CMPA

Answer 31

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

Question 32

What is Lactose Intolerance?

Answer 32

Result of enzyme deficiency rather than IgE mediated | Rarely presents in <6 y

Question 33

What are the four types of Lactose Intolerance?

Answer 33

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

Question 34

How does Lactose Intolerance present?

Answer 34

Bloating, Flatulence, Abdominal Discomfort, Loose Watery Stools Failure to thrive

Question 35

How is Lactose Intolerance normally diagnosed?

Answer 35

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

Question 36

What is the ‘Lactose Tolerance Test’?

Answer 36

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

Question 37

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

Answer 37

Hydrogen breath test Hydrogen is a by product of bacterial fermentation of undigested lactose

Question 38

How is Primary Lactose Intolerance managed?

Answer 38

Avoidance of lactose to varying extents Higher fat content is better tolerated as it slows gastric emptying

Question 39

How is Secondary Lactose Intolerance managed?

Answer 39

Fluid rescucitation may be required

Question 40

How is Developmental Lactose Intolerance managed?

Answer 40

Full lactose feeds are more likely to induce tolerance

Question 41

How is Congenital Lactose Intolerance managed?

Answer 41

Cannot breast feed Requires lactose free formula and subsequently food

Question 42

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

Answer 42

Calcium Magnesium Zinc

Question 43

Define Anaphylaxis

Answer 43

Severe life threatening systemic type 1 hypersensitivity reaction

Question 44

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

Answer 44

- Secure airway - Consider Oxygen - IV fluid bolus - Lie patient flat to promote cerebral perfusion

Question 45

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

Answer 45

0.5ml 1:1000 Adrenaline IM 100-300mg IV Hydrocortisone 10mg IV/IM Chlorphenamine

Question 46

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

Answer 46

Admit to Paediatric Ward (biphasic reaction) Confirm by measuring serum tryptase within 6 hours

Question 47

Define Allergic Rhinitis

Answer 47

IgE mediated type 1 hypersensitivity causing an inflammatory response in the nasal mucosa Can be seasonal, perennial or occupational

Question 48

How is Allergic Rhinitis managed?

Answer 48

Avoid the trigger (hoover and change pillows regularly, staying indoors in high pollen count) Oral Antihistamines Nasal Sprays (don’t sniff) (fluticasone or antihistamine)

Question 49

Give examples of the different types of antihistamine

Answer 49

Non Sedating - Cetirizine, Loratidine Sedating - Chlorphenamine, Promethazine

Question 50

Define Urticaria

Answer 50

Itchy red blotchy rash from swelling of superficial skin (secondary to mast cell activation) (Called Angio-oedema when it affects deeper tissues)

Question 51

Describe the appearance of Urticaria

Answer 51

Itchy white papule/plaque surrounded by erythematous flare

Question 52

How is Urticaria managed?

Answer 52

``` Avoid aggravating factors (overheating, stress) Topical Antipruritics (Calamine or topical menthol) Non sedating antihistamines (3-6 months) ``` If severe can give oral steroids