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Flashcards in Allergy Deck (15)
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1

Define Allergy

Allergy is a type 1 hypersensitivity reaction to certain environmental allergens.

2

Why is the incidence of allergy rising in developed countries?

- Hygiene Theory. People arn't building up a tolerance to environmental antigens as children due to better hygiene.

- Our diet becoming more processed

3

What are the risk factors for allergy?

Host
- Heredity
- Race
-Age

Environmental:
- Certain Dietary Changes
- Allergen Levels
- Altered exposure to infectious diseases in early childhood
- Environmental pollution

Occupational:
- E.g. exposure to flour, latex or wood dust

4

How do allergic reactions vary?

They can be local or systemic.

They vary based on:
- Individual
- Allergen
- Mode of introduction

5

Define an allergen?

The particle who's antigen triggers the allergic reaction.
Usually they're proteins

6

Explain how an allergy develops and a reaction occurs?

1) On 1st exposure plasma cells produce specific IgE antibodies (i.e. becoming sensitized)

2) IgE binds to mast cells

3) On re-exposure they trigger the mast cells to degranulate, giving out histamine, leukotrienes, prostaglandins & Chemotactic factors

4) Inflammatory response occurs

7

Explain the phases of an allergic reaction?

Acute response:
- Acute Inflammation
- If systemic can be anaphylaxis

Late Response:
- 2-4 hours later
- Occurs due to migration of distant leukocytes (e.g. neutrophils, lymphocytes, eosinophils & macrophages)

8

How do we classify allergy>

Using the ARIA classification

Split into intermittent vs persistent
And Mild vs Moderate/severe

9

What makes an allergy intermittent or persistent?

Intermittent if:
- <4days/wk
- OR <4 consecutive wks

Persistent:
- 4 or more days/wk
- AND 4 or more consecutive wks

10

How do we divide allergies into mild or moderate-severe?

Its moderate-severe if:
- Sleep Disturbances
- Impairs Daily Activities
- Impairs Work or school
- Symptoms are troublesome

11

How do we diagnose an allergy?

Allergic Skin Test:
- Tests skin response to known allergens

Radioallergosorbent Blood Test:
- Tests for presence & level of allergen specific IgE

Also:
- Total Serum IgE
- Nasal Allergen Challenge
- Nasal Cytology

12

How do we treat Allergies?

Allergen Avoidance is First line.

Salty Water (Saline) Spray

Pharmacotherapy:
- Steroids (topical vs systemic)
- Antihistamines
- Sodium Cromoglycate
- Anti-IgE

Immunotherapy

13

Define Allergic Rhinitis?

Allergic Inflammation of the Nasal Airways
Occurs when a person with a sensitized immune system breaths the allergen in

14

What are the risk factors for Allergic Rhinitis?

- Environmental (Same as general allergy risk factors)
- Atopy (i.e. associated with other atopic disease e.g. eczema/asthma)
- 1st Born
- Family History

15

What are the symptoms of allergic rhinitis?

Immediate:
- Sneezing
- Itching
- Nasal Blockage
- Rhinorrhoea

Late (delayed):
- Chronic Obstruction
- Hyposmia (Reduced smell due to nasal blockage preventing air flow to olfactory nerves)
- Hyperreactivity