When you should worry about a persistent cough, received from Saga Magazine, 2026 01 15

[Colin Howard]

Greetings,

I stopped smoking having had my last pipe early on Christmas Day morning, in
1988, I believe having a cough even now, might be related in some way to my
having been a smoker for 23.5 years.

Coughing is common during the winter colds and flu season, but what if it
carries on past a few weeks? Our expert guide explains when to get it
checked by a doctor.
By Jo Waters | Published - 13 Jan 2026

Whether coughs are tickly, hacking, dry, or chesty ones bringing up phlegm,
they can have a big impact, disrupting sleep at night, causing social
embarrassment, exacerbating incontinence and spreading infection.
But when do they become something to worry about?

Persistent coughs lasting more than eight weeks affect an estimated five to
10 per cent of the UK's adult population, according to some estimates.

"Coughs are one of the most common medical complaints patients see a doctor
for," says Professor James Hull, a consultant respiratory medicine
specialist at HCA's The Princess Grace Hospital and clinical lead for
chronic coughs at the Royal Brompton Hospital, both in London.

"While most are short-term, some can be more persistent, lasting many weeks
or even months. In those cases, you should seek medical help for imaging to
find out if there is a more serious underlying cause."

Most coughs are nothing to be worried about

"The first thing to say is, most causes of persistent cough are nothing to
be frightened of, at this time of year, it's mostly either an active viral
infection or an irritated, damaged lining of your airways," says Tom
Routledge, consultant thoracic surgeon and lung cancer specialist at HCA
London Bridge Hospital and Guy's and St Thomas' Hospital, both in London.

"That means your cough persists for much longer than the acute infectious
illness itself. So, you might have flu for a week or two, but it's not
unusual for a cough to persist for two or three weeks after, when your
airways are healing."

Why do we cough?

Coughing is a protective reflex which protects the lungs from foreign bodies
and helps us clear mucus.

It's triggered when nerve receptors that line the respiratory tract sense
irritants and then expel air and particles out of the lungs and throat to
clear them.

"The nerve fibres in the respiratory tract send a message up to the cough
control centre in the brain which relays a message back that causes the
closure of the airways," explains Professor Hull.

"The nerve circuit detects things which are perceived as either
structurally, physically or chemically potentially harmful to the lungs."

Coughing helps to protect our lungs from foreign bodies

What are the different causes of coughing?

Respiratory infections: "One of the most common causes of coughs," says
Professor Hull. "A virus can sensitise the cough pathways and cause a cough
which can typically last anywhere between five and 10 days after the
infection. You may cough up mucus or phlegm."

Asthma: This can cause coughing because the lining of bronchial tubes
can become inflamed, tightening surrounding muscles and narrowing the
airways, irritating nerve receptors in the airway wall.

Breathing in cold air: "This type of cough can often be mistaken for
asthma, but is actually triggered by sensors in the airways lining being
sensitive to temperature changes," says Professor Hull. "Some of these
patients will be given asthma medication and it won't work because the cause
of the problem is hypersensitivity to temperature changes."

Acid and non-acid reflux: Gases from the stomach which include acid can
irritate the oesophagus and trigger coughing.

Allergies: These include hay fever and allergic rhinitis and can cause a
chronic dry cough. Common allergy triggers include pollen, dust mites, mould
and pet dander (microscopic, flaky skin shed by furry animals such as cats,
dogs and rodents). Allergens cause inflammation in the airways and also
cause excess mucus, both of which can trigger coughs.

Postnasal drip: This is where excess mucus accumulates and drips down
the back of the throat, triggering a cough. It can be caused by allergies,
infections or acid reflux.

Prescription drug side effects: "The main culprits here are the blood
pressure drugs called ACE inhibitors," says Professor Hull. The cough often
starts months after you begin taking the medication.

Smoking: The chemicals you inhale when smoking tobacco damage small
hairs in the lining of the airways which normally keep them clear. Smokers
produce more mucus and may cough up phlegm to clear the airways.

Food triggers: "Certain foods, such as crumbly biscuits or chilli
powder, can trigger a cough if the nerve receptors which line the airways
are hypersensitive," says Professor Hull.

What treatments are there for coughs?

"Studies have shown, the majority of cough medicines are no better than
placebo," says Professor Hull.

"It's important to be well hydrated, rest and give the cough time to clear,
most will resolve within seven to 10 days. Some people find that using
manuka honey, cloves in a hot drink and/or lozenges with menthol may also be
beneficial."

Other treatments for coughs will depend on the underlying causes. For
example, a bacterial chest infection can be treated with antibiotics; a
cough caused by acid reflux can be treated with drug treatments such as
proton pump inhibitors to stop stomach acid production; and asthma can be
controlled with inhalers and inhaled steroids.

Rest and water are recommended when recovering from a cough

Can you have a 'nervous' cough?

"An estimated 1-2.5% of people over the age of 50 develop a cough which is
either persistent or recurrent and that doesn't seem to respond to
treatments and we think this is caused by a condition we now call cough
hypersensitivity syndrome," says Professor Hull.

"This is also known as a neuronal cough or a nerve hypersensitivity cough.
But it's not to say the coughing is due to someone being nervous, it's to do
with the fact their nerve fibres are sensitised. It's quite a substantial
problem."

However, Professor Hull says, in some people, coughs can be triggered by
anxiety and stressful situations such as public speaking, making
presentations or being in the audience at the theatre.

"If people are nervous or anxious, the body automatically heightens its
protective reflexes," he explains. "Some people can have nerve
hypersensitivity and coughs triggered by stress and anxiety at the same
time," he says.

"These people can feel excluded socially because they know they will cough
in certain social scenarios, such as at the cinema or when meeting groups of
people and people will move away from them or exclude them, it's an awful
thing to have."

The first drug for hypersensitivity coughs, called Gefapixant (Lyfnua), was
approved by the UK's Medicines and Healthcare Products Regulatory Agency
(MHRA) in 2023, but has not yet been approved for NHS use by the National
Institute for Health and Care Excellence (NICE) and is only available
privately.

It works by blocking receptors on sensory nerves that are overactive in
cough hypersensitivity and reduces coughs by 60% in some patients, according
to a King's College Hospital study.

When can a cough be a sign of something more serious?

A persistent cough is defined as one which lasts more than eight weeks, says
Professor Hull.

"If you have a cough which continues for longer than four to six weeks, it's
important to get it checked with medical imaging, such as a chest X-ray or a
CT scan, to rule out any serious underlying conditions.

"This evaluation should also include reviewing your medications to see if
they might be causing the cough. By considering additional symptoms, doctors
can help determine whether issues like postnasal drip, allergies or acid
reflux are contributing factors."

What are the red flags to look for?

Seek medical help if you experience any of the following:

Coughing yellow/green phlegm

Chest pain

Fever or sweats

Unexplained weight loss

Coughing up blood

"The key thing is persistence, if you have a cough above four to six weeks,
you need imaging, even if you don't have any of the red flags above,"
stresses Professor Hull. "I've seen lung cancer cases in people who only had
a mild, dry cough, you don't necessarily cough up blood."

Routledge says your doctor would also consider other concerning symptoms,
such as your breathing being less good and you being more short of breath
during and after exercising.

"These could be signs of more serious illnesses, not just lung cancer," he
explains. "If you cough up any blood even during the acute phase of an
infection, it should warrant a trip to the doctor for checking.

"In the longer term, if you look back and you haven't been feeling well for
months and/or you've been losing weight unintentionally over the last few
months accompanying your cough, that will always warrant more
investigation."

Routledge says, smokers (even those who quit decades ago) should have a
lower threshold for seeking help with the above symptoms, as they are at
higher risk.

What are the possible serious causes of coughs?

These include a number of diseases your doctor will want to rule out or
diagnose at an early stage.

Lung cancer

"The obvious worry is lung cancer," says Routledge.

"People tend to wait until they have symptoms to get checked out and in lung
cancer you don't get symptoms (such as breathlessness and coughing) until a
late stage. It is often diagnosed in A and E with very severe symptoms."

He says although newer drugs such as immunosuppressants have greatly
improved treatments for lung cancer, these are most effective if it is
diagnosed at an early stage. Five-year survival with stage 1 lung cancer is
90% compared to 4% at stage 4.

Lung cancer is still the leading cause of cancer deaths in the UK, with
33,100 people dying each year, according to Cancer Research UK.

A national lung cancer screening programme is now being rolled out across
England and also planned for Wales, identifying people aged 55 to 74 who are
smokers or who have ever smoked for a lung health check, including a CT
screening scan if judged necessary. In 2024, it was reported to have picked
up more than 5,000 lung cancers, 76% at an early stage (60% at stage 1).

The University of Aberdeen is evaluating a blood test combined with imaging
to see if it can reduce late-stage lung cancer diagnosis.

Secondary bacterial lung infections

"In the winter months particularly, a viral infection can lead to a
secondary lung infection such as pneumonia or bacterial bronchitis
(inflammation of the lungs usually caused by an infection), which may need a
course of antibiotics," says Routledge.

Lung fibrosis

Also known as pulmonary fibrosis, this is scarring of the lung tissue, which
makes it stiffer and harder to breathe. Symptoms include shortness of
breath, a dry cough and extreme fatigue.

Chronic obstructive pulmonary disease (COPD)

This is a long-term lung condition where the lungs become inflamed and
damaged, making breathing more difficult. It's usually caused by breathing
in harmful chemicals such as cigarette smoke and fumes.

A persistent cough is one of the symptoms, as is coughing up phlegm and
breathlessness. Treatments include using bronchodilators and steroids, but
giving up smoking is the most important first step.
Written by: Jo Waters

Jo Waters is an award-winning health and medical journalist who writes for
national newspapers, consumer magazines and medical websites.
She is the author of four health books, including What's Up with Your Gut?
and is a former chair of the Guild of Health Writers.

Colin Howard, living in Southern England.