Brittle asthma is one clinical phenotype of the disease at the severe end of the spectrum of asthma. Brittle asthma is of two types: type 1 and type 2. Brittle asthma is recognized by sudden life threatening attacks on the background of wide PEF variability or apparent normal airway function and significant difficulties to manage the disease. Application of the standard regimen for asthma treatment may not be sufficient to control the symptoms of brittle asthma.