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Systems: Head and Neck AB > Allergy > Flashcards

Flashcards in Allergy Deck (40)
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1
Q

What is the incidence of asthma in the UK?

A

9.4%

2
Q

What is the incidence of allergic rhinitis in the UK?

A

5.4%

3
Q

What is the incidence of eczema in the UK?

A

1%

4
Q

What is the incidence of food allergies in the UK?

A

1-2%

5
Q

What is the incidence of multiple allergies in the UK?

A

3.7%

6
Q

When did the rapid increase in allergies in the UK begin?

A

1960s

7
Q

What is the financial cost of treating allergic disorder in a year in Scotland?

A

£130 million

8
Q

Allergy

A

-A hypersensitive disorder of the immune system

9
Q

What do allergic reactions occur normally to?

A
  • Harmless environmental substances known as allergens.

- These reactions are acquired

10
Q

Allergic reaction

A

An exaggerated or inappropriate immune reaction and causes damage to the host

11
Q

What are common allergic reactions?

A
  • Eczema
  • Allergic rhinitis
  • Asthma
  • Food allergies
12
Q

Allergen

A

Antigen that causes allergic reactions

13
Q

What are allergens usually?

A

Proteins

14
Q

Systemic or localised symptoms are dependent on?

A
  • Individual
  • Allergen
  • Mode of introduction
15
Q

Where is asthma localised to?

A

Respiratory system

16
Q

Where is eczema localised to?

A

Dermis

17
Q

Give examples of fairly common food allergens.

A
  • Peanuts
  • Eggs
  • Milk
  • Dairy
18
Q

Give examples of less common food containing allergenic proteins.

A
  • Soy
  • Wheat
  • Fish
  • Shellfish
  • Fruits
  • Vegetables
  • Spices
19
Q

What are common symptoms of an allergic reaction.

A
  • Sneezing
  • Nasal congestion
  • Runny nose
  • Swelling and tenderness of the mouth
  • Difficulty breathing
  • Flushing or rash
  • Burning and itching of the skin
  • Hives
  • Nausea/vomiting
  • Abdominal cramps
  • Diarrhoea
20
Q

What is the pathophysiology of allergy?

A

IgE mediated triggering of mast cells and subsequent accumulation of inflammatory cells at sites of antigen deposition

21
Q

What happens on first exposure to allergen?

A
  • Response with T cells and B cell producing IgE

- IgE circulates in the blood and binds to an IgE specific receptor

22
Q

What is the acute response on exposure to allergen?

A
  • Ag+ specific IgE
  • Degranulation with release of histamine, cytokines, interleukins, leukotrienes and prostaglandins from their granules causing systemic effects such as vasodilation, mucous secretion, nerve stimulation and smooth muscle contraction
23
Q

When does the late phase response occur on exposure to allergen?

A

2-4 hours later

24
Q

What is the late phase response to allergen due to?

A

Migration of other leukocytes such as neutrophils, lymphocytes , eosinophils and macrophages to the initial site

25
Q

What are the host related risk factors for allergen?

A
  • Hereditary
  • Race
  • Age
26
Q

What are the environmental related risk factors for allergen?

A
  • Alterations in exposure to infectious diseases during early childhood
  • Environmental pollution
  • Allergen levels
  • Dietary changes
27
Q

How is an allergy diagnosis made?

A
  • Skin test: responses to known allergens- high NPV, up to 15% false positives
  • RAST: presence an levels of allergen-specific IgE
28
Q

What different modalities of treatment are there for allergies?

A
  • Allergen avoidance
  • Immunotherapy
  • Pharmacotherapy
29
Q

What is the traditional treatment for allergies?

A

Avoidance

30
Q

What is involved in avoiding allergens?

A
  • Avoiding or reducing exposure to the allergen in question

- Cat allergies: easy to avoid cats but difficult to avoid air-borne allergies

31
Q

Why are drugs used the treatment of allergies?

A

To prevent activation of cells and degranulation processes or to block the action of allergic mediators

32
Q

What drugs can be used in the treatment of allergies?

A
  • Antihistamines
  • Glucosteroids
  • Epinephrine
  • Theophylline
  • Cromolyn sodium
  • Antileukotrines
33
Q

What is involved in immunotherapy?

A

Controlled exposure to known allergens to reduce the severity of allergy

34
Q

What is immunotherapy useful in?

A
  • Allergic rhinitis
  • Allergic asthma
  • Allergic conjunctivitis
35
Q

What is immunotherapy not useful in?

A
  • Food allergy
  • urticarial
  • Atopic dermatitis
36
Q

How does immunotherapy work?

A
  • Desensitization: vaccinated with progressively larger doses of the allergen
  • Increasing IgG antibody production blocks excessive IgE production
  • The person builds up immunity to increasing amounts of the allergen in question
37
Q

Allergic rhinitis

A

Allergic inflammation of the nasal airways

38
Q

When does allergic rhinitis occur?

A

When an allergen is inhaled by an individual with a sensitized immune system

39
Q

What are the clinical features of an allergic response?

A
  • Sneezing
  • Coughing
  • Wheezing
  • Runny nose
  • Weepy eyes
  • Itchiness
40
Q

What are the classifications of allergic rhinitis?

A
  • Seasonal

- Perrennial