Asthma can be caused by genetic or environmental factors, i.e. it can be inherited. It is not contagious.Certain environmental triggers may cause an attack in genetically predisposed people, including: animal dander (fur of pets), pollen, dust mites, insects or pests, respiratory infections, air pollution, weather or temperature changes, cigarette smoke, certain drugs e.g NSAIDs (a group of anti-inflammatory medicines including aspirin), or beta blockers (a group of medicines to lower blood pressure or heart rate). Triggers vary amongst patients.

Asthma can affect both children and adults. Some children may grow out of it but for others, it can be a chronic condition.

During an attack, the airway lining becomes inflamed and swollen. The airway muscles contract, and thick phlegm (mucus) is produced.

The patient may cough, wheeze (breathe with a high pitched sound) and experience difficulty breathing (shortness of breath). If untreated, a severe attack can be fatal. Severity varies amongst individuals.

Asthma cannot be cured but it can be controlled. Patients can live normal, active lives and sleep through the night without symptoms.

Sometimes symptoms are typical and the diagnosis is easily made by a doctor. If there is doubt then some simple tests may be arranged. The two commonly used tests are called spirometry and assessment with a peak flow meter.

There are two main types of treatment: short-acting medicine that relieves asthma during an attack (bronchodilators) and longer acting or preventative medicine that helps to stop symptoms from occurring (eg, inhaled steroids). Treatment can be given in various forms. Usually, the first treatment your doctor will prescribe is an inhaler that can be used during an attack to relax the muscles and widen the airways, or to prevent symptoms occurring when a known trigger is present, such as before exercise.