extrinsic asthma (features of)
Last reviewed 01/2018
- history of allergy:
- the most common allergen involved in the development of extrinsic asthma worldwide are the faecal particles of the house-dust mite
- other common allergens include:
- occupational allergens:
- IgE related causes include allergens from flour and grain, e.g. in farmers
- complex salts of platinum in metal refining
- acid anhydrides used in industrial coatings
- drugs - NSAID's and food additives such as tartrazine; patients with extrinsic asthma are not aspirin sensitive
- aspergillus
- family history of atopy
- early onset
- attacks often seasonal
- occasional polyps
- investigation - eosinophilia; elevated IgE; skin prick test positive
- good response to beta agonists and disodium chromoglycate