In some individuals the symptoms of an
asthma attack are characterized by
chronic breathing difficulties. In
others it is an illness that comes and
goes and is marked by episodes with
symptoms that may be triggered by a
number of events, including upper
respiratory infection, airborne
allergens, and exercise.
When existing asthma suddenly becomes
worse, this is referred to as an asthma
attack. The clinical hallmarks of an
asthma attack are shortness of breath
(dyspnea) and wheezing. Some victims
present primarily with coughing, and in
the late stages of an asthma attack,
air motion may be so impaired that no
wheezing may be heard. When present the
cough may sometimes produce clear
sputum. The onset may be sudden, with a
sense of constriction in the chest,
breathing becomes difficult, and
wheezing occurs.
Signs of an asthmatic episode are
wheezing, rapid breathing (tachypnea),
prolonged out breath (expiration), a
rapid heart rate (tachycardia), lung
sounds which are audible through a
stethoscope, and over-inflation of the
chest.
During very severe attacks, an asthma
sufferer can turn blue from lack of
oxygen, and can experience chest pain
or even loss of consciousness. Severe
asthma attacks may lead to respiratory
arrest and death. Despite the severity
of symptoms during an asthmatic
episode, between attacks an asthmatic
may show few signs of the disease.



