Infections and post nasal drip

Viral infections of the respiratory tract, such as colds, are the most common cause of acute coughs. A cough accompanied by a fever, fatigue and muscular aches or pain could be due to a flu infection. Upper respiratory tract viral infections can also trigger post nasal drip (PND). In PND, mucus drips from the back of the nasal passages into the throat, triggering a cough. PND can also occur with some allergies.

Other infections that cause coughs include:

Bronchiolitis €“ a lower respiratory tract infection that causes inflammation of the smaller airways in the lungs (bronchioles). This is often caused by respiratory syncytial virus (RSV). Children under two years old are particularly susceptible and may suffer cold-like symptoms, fever, shallow rapid breathing, coughing and wheezing.

Croup €“ inflammation and swelling of the larynx, usually triggered by a viral infection. This is a potentially dangerous condition that most commonly occurs in young children. Symptoms tend to come on at night and include a barking cough with hoarse breathing.

Whooping cough (pertussis) €“ a bacterial infection caused by Bordetella pertussis. The initial symptoms are similar to a cold (i.e. a runny nose, fever and mild coughing). The condition then progresses to include bouts of severe coughing. The sufferer may find it difficult to breathe while coughing and gasp for air, producing the characteristic 'whoop' sound. They may also turn red in the face, vomit, and have nosebleeds or even seizures while coughing. This type of cough can continue for several weeks following treatment of the initial infection.

The common cold often causes an acute, dry cough

Tuberculosis (TB) €“ caused by the bacterium Mycobacterium tuberculosis. Symptoms include fever, tiredness, weight loss, night sweats and persistent coughing, which may include blood-streaked phlegm. Occasionally, infection can affect the lymph nodes, skin and bones. TB can be fatal if untreated.

Asthma

Asthma is characterised by widespread, reversible narrowing of the airways within the lungs. It is a common cause of chronic cough in adults and children. In some sufferers, a night-time cough is the only symptom, while others suffer wheezing and shortness of breath. Coughing usually stops if the asthma is appropriately managed.

Gastroesophageal reflux disease 

Not just related to heartburn and indigestion, gastroesophageal reflux disease (GORD) can cause chronic cough in adults and children. Reflux occurs when the acidic contents of the stomach are pushed upwards into the oesophagus. This irritates the oesophagal lining and triggers coughing. This can be difficult to diagnose as many sufferers of GORD-related cough don't complain of heartburn-type symptoms.

Chronic lung conditions

Conditions such as chronic bronchitis, bronchiectasis and emphysema can all affect a person's ability to clear mucus from their lungs. This results in symptoms including chronic cough and shortness of breath.

Smoking

Only a small percentage of chronic cough sufferers have lung cancer. However, the link between smoking and lung conditions, such as chronic bronchitis, is well established. Smokers often assume a cough is just due to their habit and therefore may be slow to seek treatment. Any change or worsening in a smoker's cough should be referred to the pharmacist. When advising smokers on their cough symptoms, take the opportunity to discuss smoking cessation options. The symptoms of coughing ease quickly after quitting and often stop completely within three to nine months. Breathing and wheezing will also improve.

Other causes

In rare cases, a cough is a symptom of a serious condition such as heart failure, a pulmonary embolism (a blood clot in the lungs) or cystic fibrosis. Coughing can also occur following exposure to irritants such as smoke, paint fumes, highly scented aerosols or a small foreign object getting stuck in the airways. A cough can also be a nervous habit, or may be linked to emotional or psychological problems, particularly in children.