<unk>  is a type of<unk>  distinguishable from other forms by recurrent, severe attacks. There are two subtypes divided by symptoms: Type 1 and Type 2, depending on the stability of the patient's maximum speed of expiration, or peak expiratory flow rate (PEFR). Type 1 is characterized by a maintained wide PEF variability despite considerable medical therapy including a dose of inhaled steroids, and Type 2 is characterized by sudden acute attacks occurring in less than three hours without an obvious trigger on a background of well controlled<unk> .<unk>  is one of the "unstable" subtypes of "difficult<unk> ", a term used to characterize the less than 5% of<unk>  cases that do not respond to maximal inhaled treatment, including high doses of corticosteroids combined with additional therapies such as long-acting beta-2 agonists.
Brittle asthma
Thunderstorm asthma
Yokkaichi asthma
Reactive airway disease
Cardiac asthma
Asthma
Mineral dust airway disease
Occupational asthma