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Statistics

Allergic Asthma

OVERVIEW

 

    • Prevalence
    • Pre-school wheeze
    • Asthma
    • Allergen exposure and asthma
    • The Allergic March

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  • Asthma Management

Pre-school wheeze

Transient early wheeze

Risk factors

  • Reduced pulmonary function in infancy
  • Prematurity
  • Male gender
  • Exposure to siblings and day care
  • Prenatal and post-natal smoking exposure
  • Resolves around the age of 3 yrs

Non-atopic viral wheeze

  • Principally due to recurrent viral infections
  • Non-atopic wheezers have normal lung function in early life but intermittent airways obstruction secondary to viral infections
  • Origin of wheezing in these children is not clear

Persistent atopic wheeze

  • First episode usually after infancy
  • Discrete attacks with symptom-free intervals
  • Symptoms worse at night
  • Family history of asthma or atopy
  • Elevated serum IgE and blood eosinophilia
  • Bronchodilator and corticosteroid responders
  • Normal lung function in infancy
  • Develop asthma in later childhood

Asthma

Allergic asthma

  • Allergic asthma is the most common form of asthma
  • Many of the symptoms of allergic and non-allergic asthma are the same
  • However, allergic asthma is triggered by inhaling allergens

How much asthma is atopic?

Allergen exposure and asthma

Allergen exposure and asthma

  • Indoor allergen exposure, allergen specific sensitization and asthma
  • Bell-shaped curve relationship
  • Environment * environment interactions
  • Endotoxin and HDM
  • Gene * environment interactions
  • CD14 (LPS receptor) and endotoxin

Allergen avoidance

  • HDM reduction measures to prevent asthma – NO
  • HDM reduction measures in HDM sensitized individuals for symptom relief:
  • Asthma – NO
  • Perennial allergic rhinitis – YES (extensive only)
  • Pet dander control for allergic asthma
  • No trials on pet allergen reduction or rehousing – ?

The Allergic March

Sensitization and allergic disease

Sensitization and allergic disease

Number of food allergies and asthma

Severity of food allergy and asthma

Food allergy causes respiratory symptoms

 

Allergic rhinitis and asthma

  • 19–38% AR vs. 3–5% general population
  • Allergic rhinitis almost always present in asthma
  • 78% asthmatics vs 20% general population
  • AR increases asthma severity risk
  • 3-fold risk of frequent wheezing attacks
  • 10-fold risk of frequent GP visits for asthma

Immunotherapy for AR in children

Asthma Management

Asthma in the UK

  • UK rates of wheeze 2-3 times higher than rates in Europe, but mortality is 5-10 times higher
  • Emergency admission rate for asthmatic children 26-642/100,000 (25-fold variation) in 2012

NRAD – 195 deaths 2012-2013

  • Excessive prescription of reliever medication
  • Inadequate prescription of preventer medication
  • Inappropriate prescribing of LABAs
  • 23% had personalised asthma action plan (PAAP)
  • Use of PAAP reduces risk of hospital admission 4-fold

NRAD – 18 deaths in children

  • Majority of children dies before reaching hospital
  • 8 out of 10 (80%) aged <10 years
  • 13 out of 18 (72%) aged 10 – 19 years
  • 43% were managed only in primary care
  • 78% aged 10-19 years died between March-Sept
  • 39% had known allergic comorbidities

NRAD Recommendations

  • PAAP in all children
  • Details of asthma triggers
  • Current asthma treatment
  • What to do in exacerbation and how to seek help
  • Review at least annually
  • Inhaler technique training
  • Compliance with preventer treatment
  • Minimise exposure to allergens and smoke
  • 12 reliever prescription should trigger urgent review
  • How, why and when they should use asthma medication

New BTS guidelines – 2014

Summary

  • Atopic wheeze and allergic asthma
  • Allergens induce asthma but ? causation
  • Asthma comorbities
  • Treat asthma to prevent fatal food induced anaphylaxis
  • Treat AR to reduce asthma exacerbations
  • Personalised asthma action plan reduces asthma hospitalisations 4-fold

Timing of allergic march

 

 

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