Notes
History & examination
Key diagnostic factors
- presence of risk factors (common)
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- Key risk factors include a FHx of asthma, exposure to allergens (e.g., dust mites, pets, tobacco smoke), or history of atopic diseases (e.g., eczema, allergic rhinitis).
- recent upper respiratory tract infection (common)
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- With a recent sinusitis or common cold, symptoms are typically exacerbated.
- dyspnoea (common)
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- Precipitated by allergen exposure, exposure to cold air, tobacco smoke, or particulates; worse with emotions such as laughing hard.
- May wake patient from sleep.
- cough (common)
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- Precipitated by allergen exposure, exposure to cold air, tobacco smoke, or particulates; worse with emotions such as laughing hard.
- May wake patient from sleep.
- expiratory wheezes (common)
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- Precipitated by allergen exposure, exposure to cold air, tobacco smoke, or particulates; worse with emotions such as laughing hard.
- Polyphonic, high-pitched expiratory wheezes are typical of asthma.
- nasal polyposis (common)
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- Appear as single or multiple polyps in the nasal cavity.
Risk factors
Strong
- FHx
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- A parental history of asthma is a major risk factor for early development of asthma. [1]
- Multiple genes are implicated that predispose people to hyper-responsiveness to environmental aetiological triggers.
- allergens
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- Common allergens include cats; dogs; cockroaches; dust mites; fungal spores; tobacco smoke; fumes from chemicals, such as bleach; and pollen from trees, weeds, and grass.
- Professions commonly affected by occupational allergens include bakers, farmers, carpenters, and people involved in manufacturing plastics, foams, and glues.
- atopic history
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- History of eczema, atopic dermatitis, allergic rhinitis is strongly associated.
Weak
- nasal polyposis
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- Inflammatory syndrome of nasal polyposis, aspirin intolerance, and asthma. [36]
- Nasal polyps are associated with late-onset versus childhood asthma.
- obesity
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- Increasing rates of obesity appear to parallel increasing rates of asthma prevalence, but the cause of the correlation is uncertain. [1]
- Postulated mechanisms include reduced lung and tidal volume (promoting airway narrowing), low-grade systemic inflammation, effect of co-morbidities, or a common aetiology. [37] [38]
- gastro-oesophageal reflux
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- Prevalent in patients with poorly controlled asthma. However, treatment with a proton-pump inhibitor does not improve asthma control. [39]
Last updated: Jan 23, 2013
