Aetiology

Asthma is a complex disease with underlying multi-gene association interacting with environmental exposure. [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20]

The genes associated with the disease include, but are not limited to, ADAM 33, [6] [21] [22] [23] [24] [25] [26] dipeptidyl peptidase 10, [27] [28] PHD finger protein 11, [27] [28] prostanoid DP1 receptor, [27] [28] chromosome 12q, [29] and polymorphisms in tumour necrosis factor (TNF). [30] [31]

Patient genetic make-up may predispose them to hyper-responsiveness to environmental aetiological triggers. Those triggers include viral infections (e.g., rhinovirus, respiratory syncytial virus, human metapneumovirus, and influenza virus), bacterial infections (Mycoplasma pneumoniae or Chlamydia pneumoniae), allergen exposure (e.g., tree, grass, or weed pollen; fungi; or indoor allergens), occupational exposures (e.g., animal or chemical), food additives and chemicals (e.g., metabisulphites), irritants, or aspirin in predisposed people. [16]

Strong emotions can also precipitate attacks, but often no clear aetiology can be identified.