Allergy Diagnosis and Treatment

Question 1

What is allergy?

Answer 1

Inappropriate/harmful response to foreign substances that are otherwise not harmful to body
Mediated largely by IgE

Question 2

What is an allergen?

Answer 2

Generally protein that elicits IgE response in allergic individuals

Question 3

What are some symptoms of an allergy if the allergen is inhaled?

Answer 3

Rhinitis

Asthma

Question 4

What are some symptoms of an allergy if the allergen comes into contact with the skin?

Answer 4

Acute contact urticaria

Question 5

What are some symptoms of an allergy if the allergen is swallowed?

Answer 5

Oral allergy syndrome
Cramping/vomiting/diarrhoea
Can lead to anaphylaxis

Question 6

What is considered a positive skin prick test?

Answer 6

3+ mm wheal

Question 7

What are the advantages of a skin prick test?

Answer 7

Highly sensitive
In vivo exposure to allergen
Convenient
Results obtained within 20 mins

Question 8

What are the disadvantages of a skin prick test?

Answer 8

Small potential for anaphylaxis
May lack specificity due to
- Sensitised by asymptomatic individuals
- Irritant false positive reactions
Usually need specialist clinic

Question 9

What is the role of serology in the diagnosis of allergies?

Answer 9

Measure allergen-specific IgE

Radio-allergosorbent test (RAST) now redundant but commonly used name for other serology tests used now

Question 10

What are the advantages of in vitro assays?

Answer 10

Availability
Safety
Specific, particularly at high level
Standardised

Question 11

What are the disadvantages of in vitro assays?

Answer 11

May get false positives with elevated total IgE

Question 12

What is the gold standard for allergy diagnosis?

Answer 12

Challenge tests

Question 13

When are challenge tests used in the diagnosis of allergy?

Answer 13

When RAST and skin prick tests negative/discordant and good clinical story

Question 14

What is allergen immunotherapy?

Answer 14

Only current allergy therapy to provide prolonged improvement/cure
Efficacy limited by side effects
Initiated and/or supervised by allergist

Question 15

For what is allergen immunotherapy indicated?

Answer 15

Venom allergy
Allergic rhinitis
Mild, well controlled allergic asthma
- Stable symptoms
- FEV1 >70% predicted

Question 16

What is sublingual immunotherapy?

Answer 16

Doses of allergen extract self-administered daily by patient sublingually
Held for 2 mins under tongue > swallowed
Effective as subcutaneous immunotherapy
Minimal risk of anaphylaxis
Extracts more expensive

Question 17

What is anaphylaxis?

Answer 17

Serious allergic reaction that may cause death
Generalised serious IgE-mediated allergic reaction usually involving
- Cardiovascular
- Hypotension
- Respiratory tract
- Asthma
- Laryngeal oedema

Question 18

Are atypical presentations of anaphylaxis common?

Answer 18

Not uncommon, particularly in very old/very young

Question 19

What is the mechanism of anaphylaxis?

Answer 19

Massive mediator release primarily from mast cells and basophils
Vasodilation, fluid extravasation, bronchial smooth muscle contraction, mucosal oedema
Death due to
- Shock
- Hypoxaemia

Question 20

What are mild symptoms of anaphylaxis?

Answer 20

Pruritis
- Hand
- Groin
Urticaria
Flushing
Vomiting
Diarrhoea

Question 21

What are moderate and severe symptoms of anaphylaxis?

Answer 21

Angioedema
- Lips
- Tongue
- Larynx
Wheeze
Asthma
Hypotension
Loss of consciousness

Question 22

What are the main causes of fatal anaphylaxis?

Answer 22

Food allergy, especially nuts
Insect venom
Drugs

Question 23

What are the risk factors for fatal food-related anaphylaxis?

Answer 23

Associated asthma
Lack of self-injectable adrenaline
Young adults
Alcohol
Extreme sensitivity

Question 24

What are the main insect venom allergies?

Answer 24

Bees
European wasps
Jumper ants

Question 25

In whom are latex allergies mainly seen?

Answer 25

Healthcare workers | Spina bifida patients

Question 26

What symptoms are latex allergies most commonly associated with?

Answer 26

Irritant/contact dermatitis

Question 27

Which allergens can latex allergens be cross-reactive with?

Answer 27

Banana Avocado Kiwi

Question 28

Which drugs are common causes of drug allergies?

Answer 28

``` Antibiotics - Penicillins - Cephalosporins Radiocontrast agents Anaesthetics - Muscle relaxants NSAIDs Natural medicines ```

Question 29

What are the principles of long-term therapy in allergy management?

Answer 29

Avoidance Education on action plan Medical alert bracelet

Question 30

Why should IV adrenaline be avoided?

Answer 30

Associated with significant adverse effects > best to deliver IM

Question 31

Is prescription of an adrenaline auto-injector recommended for a drug allergy?

Answer 31

No, but would be good to have on hand

Question 32

What is the most common cause of anaphylactic deaths?

Answer 32

Medications

Question 33

What are non-specific treatments for allergies?

Answer 33

``` Antihistamines Corticosteroids Adrenaline Leukotriene antagonists Anti-IgE Abs ```