Allergy

Question 1

What are the main food allergens?

Answer 1

1. Shellfish eg. molluscs
2. Crustacean
3. Sesame
4. Peanuts
5. Tree nuts
6. Cow’s milk
7. Sulphur
8. Lupin
9. Mustard seeds
10. Gluten
11. Celery
12. Eggs
13. Fish
14. Soya

Question 2

Allergy vs intolerance

Answer 2

Allergy - type 1 hypersensitivity of immune system to allergens, mediated by IgE
Intolerance - body lacks chemical or enzyme needed to digest food

Question 3

What are the major allergic diseases?

Answer 3

• Allergic rhinitis/conjunctivitis
• Asthma
• Atopic dermatitis/eczema
• Urticaria
• Insect allergy
• Drug allergy
• Food allergy

Question 4

What is an EATERS hx?

Answer 4

Exposure
Allergen
Timing
Environment
Reproducibility
Sx

Question 5

What are the presenting sx of IgE mediated allergic reaction?

Answer 5

Skin - pruritis, erythema, acute urticaria and angioedema
GI - angioedema of lips, tongue, palate, oral pruritis, N+V+D
Resp - wheeze, cough, blocked nose, sneeze, itch
CVS - pallor, drowsy, hypotensive

Question 6

What are the presenting sx of non IgE medited allergic reaction?

Answer 6

Skin - pruritis, eczema
GI - food refusal or aversion, abdo pain and colic, GORD, loose or freq stools, constipation, pallor and tiredness, faltering growth

Question 7

What are the ix into suspected allergy?

Answer 7

• Skin prick test - sensitisation not allergy
• Immunoassay of serum IgE - sensitisation not allergy
• Food challenge testing - gold standard but not done often

Question 8

What is the management of allergy?

Answer 8

Non sedating antihistamine eg. cetirizine, fenofexadine
Steroids eg. beclomethasone intranasal steroid spray for allergic rhinitis
IM adrenaline in anaphylaxis

Question 9

What is the presentation of anaphylaxis?

Answer 9

Rapid onset:
Urticaria
Itching
Angio oedema
Abdo pain
SOB, wheeze
Swelling of larynx = stridor
CVS sx - hypotension, tachy, shock

Question 10

What is the management of anaphylaxis?

Answer 10

A - secure airway
B - O2, salbutamol if wheeze
C - bolus IV fluid
D - lie pt flat
E - look for flushing, urticaria, angiooedema
IM adrenaline, repeat after 5 mins, antihistamines, steroids eg. IV hydrocortisone

Question 11

How do you manage anaphylaxis once stable?

Answer 11

Period of observation - watch for biphasic reactions
Serum mast cell tryptase measured w/i 6 hours, will be high
Patient and child education - BLS, epipen technique

Question 12

What are the indications for having an epipen?

Answer 12

• Asthma requiring inhaled steroids
• Anaphylaxic reactions
• Adolescents
• Rural locations
• Nut or insect sting allergies
• Significant co morbid

Question 13

What is the technique for using an epipen?

Answer 13

1. Remove safety cap on non needle end
2. Needle end down - blue to the skin, orange to the thigh
3. Jab device into outer mid 1/3 thigh, hold for 10 secs
4. Remove the device and gently massage for 10 secs
5. Phone 999

Question 14

What are the causes of acute urticaria and chronic urticaria?

Answer 14

Acute - allergies, dermatitis, meds, viral infections, insect bite
Chronic - autoimmune condition, can be idiopathic or have certain triggers, or underlying autoimmune condition eg. SLE

Question 15

What can trigger chronic urticaria?

Answer 15

Sunlight
Temp change
Exercise
Strong emotions
Hot or wold weather
Pressure - dermatographism

Question 16

What is the management of urticaria?

Answer 16

Antihistamine - fexofenadine most common choice for chronic
Can use oral steroids in short course for severe flares
V problematic - montelukast, monoclonal Abs, ciclosporin

Question 17

How do you manage allergic rhinits?

Answer 17

• Oral antihistamines prior to exposure
• Nala corticosteroids sprays eg. fluticasone
• Nasal antihistamines
• Avoid trigger - stay indoors, hoovering, changing pillows, no pets

Question 18

What are the different types of antihistamines?

Answer 18

Non sedating - cetirizine, fexodenadine, loratadine
Sedating - chlorphenamine, promethazine