allergy Flashcards
1
Q
Features of an allergy
A
- Rapid onset
- Histamine mediated reactions
- Urticaria, itching, angioedema, pallor/sweating, wheeze
- Improvement with antihistamines
- Relatively quick resumption of symptoms
2
Q
Aetiology
A
- Food
- Contact e.g. bee/ wasps
- Environmental allergen
- Drugs e.g. amoxycillin
- Exercise
- Idiopathic
3
Q
Types of food which causes allergies?
A
o Milk – not IgE o Hen’s egg o Peanut- LEGUME FAMILY- closer to a pea/ legume o Tree nuts o Soya o Wheat o Fish o Sesame
4
Q
Severity of an allergy and presentations?
A
Severity -Mild/moderate o Angioedema o Urticaria/rash -Severe: o Angioedema of the airway o Bronchospasm o Hypotension
5
Q
Investigations?
A
- Skin prick test
- Specific IgE
- Oral food challenge
6
Q
Pros and cons of a skin prick?
A
Pros: o Easy o Quick o Non-invasive o Immediate results o Cheap o Negative SPT is an excellent predictor for negative IgE mediated food reaction in patients with anaphylaxis
Cons
- Need to stop anti-histamines
- Should not do on broken skin
- Risk of anaphylaxis
- Dermatographism : drawing on skin which leads to urticaria
- Over interpretation of positive results
7
Q
Pros and cons of Specific IgE
A
Pros:
oNo need to stop antihistamines
oNo risk of reaction
Cons:
oExpensive and invasive
oDelay in obtaining results – about 2 weeks
oLess sensitives and specific than SPT -more false positives
oHighly unreliable results
8
Q
What is the GOLD standard for Investigation?
A
Oral food challenge
9
Q
What is you can’t find an allergen?
A
- As needed: non sedating anti-histamines
- Regular non-sedating anti-histamines
- Leukotriene antagonist or H2 receptor antagonist
10
Q
Risk factors for anaphylaxis
A
- Asthma
- Stress
- Exercise
- Viral infection
- Alcohol
11
Q
Treatment for anaphylaxis?
A
Adrenaline pens
12
Q
Effects of adrenaline?
A
- Reverses peripheral vasodilatation
- Increases peripheral vascular resistance
- Improves BP and coronary perfusion
- Decreases angioedema
- Causes bronchodilation
- Decreases the release of inflammatory mediators
13
Q
Treatment for allergy
A
- Allergen avoidance
- Anti-histamines
- Dietary advice
- Optimise asthma control
- Adrenaline for anaphylaxis
14
Q
What is an allergy to fruit and veg also known as and how is it managed?
A
ORAL ALLERGY SYNDROME o Peeling or cooking reduces symptoms o Antihistamine o Avoid o Does not cause anaphylaxis
15
Q
Egg allergy
A
- More common in children
- Most children grow out of it by age 5
- Mild and benign
- Tolerate well cooked eggs first then raw: egg ladder
