Allergy Diagnosis and Treatment Flashcards Preview

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Flashcards in Allergy Diagnosis and Treatment Deck (33)
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1
Q

What is allergy?

A

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

2
Q

What is an allergen?

A

Generally protein that elicits IgE response in allergic individuals

3
Q

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

A

Rhinitis

Asthma

4
Q

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

A

Acute contact urticaria

5
Q

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

A

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

6
Q

What is considered a positive skin prick test?

A

3+ mm wheal

7
Q

What are the advantages of a skin prick test?

A

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

8
Q

What are the disadvantages of a skin prick test?

A
Small potential for anaphylaxis
May lack specificity due to
- Sensitised by asymptomatic individuals
- Irritant false positive reactions
Usually need specialist clinic
9
Q

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

A

Measure allergen-specific IgE

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

10
Q

What are the advantages of in vitro assays?

A

Availability
Safety
Specific, particularly at high level
Standardised

11
Q

What are the disadvantages of in vitro assays?

A

May get false positives with elevated total IgE

12
Q

What is the gold standard for allergy diagnosis?

A

Challenge tests

13
Q

When are challenge tests used in the diagnosis of allergy?

A

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

14
Q

What is allergen immunotherapy?

A

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

15
Q

For what is allergen immunotherapy indicated?

A
Venom allergy
Allergic rhinitis
Mild, well controlled allergic asthma
- Stable symptoms
- FEV1 >70% predicted
16
Q

What is sublingual immunotherapy?

A
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
17
Q

What is anaphylaxis?

A

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

18
Q

Are atypical presentations of anaphylaxis common?

A

Not uncommon, particularly in very old/very young

19
Q

What is the mechanism of anaphylaxis?

A

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

20
Q

What are mild symptoms of anaphylaxis?

A
Pruritis
- Hand
- Groin
Urticaria
Flushing
Vomiting
Diarrhoea
21
Q

What are moderate and severe symptoms of anaphylaxis?

A
Angioedema
- Lips
- Tongue
- Larynx
Wheeze
Asthma
Hypotension
Loss of consciousness
22
Q

What are the main causes of fatal anaphylaxis?

A

Food allergy, especially nuts
Insect venom
Drugs

23
Q

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

A
Associated asthma
Lack of self-injectable adrenaline
Young adults
Alcohol
Extreme sensitivity
24
Q

What are the main insect venom allergies?

A

Bees
European wasps
Jumper ants

25
Q

In whom are latex allergies mainly seen?

A

Healthcare workers

Spina bifida patients

26
Q

What symptoms are latex allergies most commonly associated with?

A

Irritant/contact dermatitis

27
Q

Which allergens can latex allergens be cross-reactive with?

A

Banana
Avocado
Kiwi

28
Q

Which drugs are common causes of drug allergies?

A
Antibiotics
- Penicillins
- Cephalosporins
Radiocontrast agents
Anaesthetics
- Muscle relaxants
NSAIDs
Natural medicines
29
Q

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

A

Avoidance
Education on action plan
Medical alert bracelet

30
Q

Why should IV adrenaline be avoided?

A

Associated with significant adverse effects > best to deliver IM

31
Q

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

A

No, but would be good to have on hand

32
Q

What is the most common cause of anaphylactic deaths?

A

Medications

33
Q

What are non-specific treatments for allergies?

A
Antihistamines
Corticosteroids
Adrenaline
Leukotriene antagonists
Anti-IgE Abs