A dry cough is a cough where no phlegm or mucus is produced
(known as non-productive). A dry cough is irritating and usually
associated with a tickly throat. Dry coughs are often caused by
viral illnesses such as colds and flu, but they can also be caused by
allergies or throat irritants.
Specific treatment for a dry cough will depend on the cause of the
cough.
How long does a cough
normally last?
Coughs associated with a cold or the flu tend to last a week or 2,
most clearing up within about 3 weeks. A post-viral cough may
persist for several (up to about 8) weeks after a viral illness, while
some coughs persist for longer and are usually a sign of an
underlying problem.
In adults and children, a cough is described as acute (short term)
if you have been coughing for up to 2 weeks.
In adults, a cough that lasts for more than 8 weeks is described as
a chronic (ongoing) persistent cough.
In children, a cough that lasts 2 to 4 weeks is called a prolonged
acute cough. A cough that lasts more than 4 weeks is considered
to be a chronic cough.
Causes of dry cough
A dry cough is often the result of:
a viral illness, such as a cold or influenza (the flu), or COVID-
19 the disease caused by SARS-CoV-2 – the novel coronavirus; or
a post-viral, or post-infective, cough (cough that persists for
weeks after a viral illness).
However, a dry cough may be a result of other problems, such as:
asthma;
gastro-oesophageal reflux;
smoking;
allergic rhinitis (hay fever) due to inhaling substances you
are allergic to, such as pollen, dust or pet dander;
post-nasal drip (the drainage of mucus secretions from the
nose or sinuses down the back of the throat – also known as
upper airway cough syndrome);
laryngitis (inflammation of the larynx, also known as the
voice box);
whooping cough;
obstructive sleep apnoea and snoring;
habit cough (a cough that is only present in the daytime and
not caused by illness – it most often affects school-aged
children);
an inhaled foreign body (e.g. food or other objects accidently
being inhaled – usually in babies and small children);
certain types of lung disease known as interstitial lung
disease; or
a side effect from a medicine (for example, cough is a
possible side effect of most ACE inhibitors – often prescribed for
high blood pressure).
Other, less common, causes of a dry cough include:
heart failure;
pulmonary embolism (a blood clot in the lungs); or
lung cancer.
A dry cough can be aggravated by:
breathing cold, dry air;
air pollution;
inhaled irritants such as dust or smoke;
exposure to tobacco smoke;
excessive use of your voice; or
a change in temperature.
Complications
A persistent dry cough can cause problems, including the
following complications.
Repeated coughing can lead to urinary incontinence in
women, especially older women, pregnant women and those
who have been pregnant.
Interrupted sleep resulting in tiredness is a common
problem for people with a persistent cough.
Severe or uncontrollable coughing fits can sometimes
cause vomiting.
Headaches may result from a persistent cough.
Can I hurt myself coughing?
When a cough is severe, pulled chest muscles and even fractured
ribs are a possible complication.
Diagnosis and tests
Your doctor will ask about your cough and any other symptoms
you may have, and perform a physical examination. Depending
on your age, history and examination, your doctor may order
tests such as:
a chest X-ray;
a throat swab (sample of secretions from the back of your
throat which can be tested for infections);
lung function tests; or
allergy tests.
Dry coughs are often related to a viral illness and in most cases
special tests are not needed.
