What should you know about sudden shortness of breath causes?

A wheeze, cough and chest tightness can point toward Asthma; irritation and mucus may occur with Acute Bronchitis, COPD or Bronchiectasis. Anaemia can limit oxygen delivery and cause breathlessness with fatigue or a pounding heartbeat. Angina may cause pressure or discomfort with exertion, while Atrial Fibrillation can produce an irregular racing pulse and reduced exercise tolerance. Anaphylaxis can develop quickly with hives, facial swelling, throat tightness or vomiting after an exposure.

These clues guide assessment but do not confirm a diagnosis. The onset, activity, pain, pulse sensation, fever, cough, exposures and previous lung or heart problems are useful details to share.

Stop what you are doing and sit upright. Note the time of onset and whether speaking, walking or lying down changes the sensation. Follow an existing asthma or allergy action plan exactly, including prescribed rescue medicine. Avoid exertion and smoke. If this is a first episode, it is severe, or the cause is unclear, contact urgent medical services rather than trying to identify the condition yourself.

Emergency help is needed for breathlessness that is severe, worsening or present at rest; chest pain or pressure; fainting; confusion; blue or grey lips; coughing blood; inability to speak normally; or swelling of the mouth, tongue or throat. Symptoms after a food, medicine or insect sting may signal Anaphylaxis. Do not travel alone when you feel faint or cannot breathe comfortably.

Which features make an airway, heart, blood or allergic cause more likely? Do I need breathing tests, heart checks or blood tests? What action plan should I follow if the sensation returns?