When should you not ignore a cough?

The start of the year brings a sense of optimism for many - and an irritating cough for nearly all.

With cold and flu season up us, homes, offices and trains are filled with people spluttering.

While many dismiss it as just an annoyance, coughing can be a sign of something sinister.

READ MORE: 5 everyday places cold and flu viruses linger

“A cough can be an inconvenience, but often it is no cause for concern and will typically go away within a couple of weeks, or as you recover from an illness,” Dr Daniel Atkinson, clinical lead at Treated.com, told Yahoo UK.

“However, there are a number of situations where a cough should not be ignored, as it could be a sign of a more serious health issue.

“Seek medical advice for your cough if your blood pressure is low.”

This can be checked by a GP or pharmacist, or via an-at home test. Blood Pressure UK recommends the most accurate ones.

Signs of low blood pressure include dizziness, blurred vision, weakness, confusion and fainting, according to the NHS.

Laboured breathing and coughing to the point of exhaustion should also raise alarm bells, Dr Atkinson adds.

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“Check your heart rate too,” he said.

“If it’s beating at more than 130 beats a minute, seek medical help.

“The cough could be a symptom of a much more serious illness, so be sure to see a doctor as soon as you can.”

Coughs can be productive, those that produce phlegm, or “dry”.

Productive coughs with blood in the mucus could be a red flag.

“A small amount once or twice may not be a concern, but if it keeps happening, your doctor should know,” Dr Atkinson said.

“It could be down to an infection or a more difficult illness like pneumonia.

“Coughing up blood, as well as a cough that won’t budge, can be a sign of lung cancer.

“If you’re finding this, and maybe experiencing other symptoms like breathlessness and fatigue, it’s important you see your doctor as soon as possible.”

READ MORE: What’s the difference between a cold and flu?

If you feel otherwise well, be aware of a cough that lingers for more than a few weeks.

“An ongoing cough could be linked to something like asthma or bronchitis, so it’s worth raising your continuing cough with a medical professional, to be on the safe side,” Dr Atkinson said.

Waking in the middle of the night to cough, and wheeze, can be another sign of asthma.

When it comes to youngsters, a hacking cough should be a signal something is awry.

“Children can develop noisy breathing, hoarseness and a barking cough as part of a viral infection known as croup,” Dr Sarah Brewer, medical director at Healthspan, told Yahoo UK.

This usually gets better on its own. See a GP if the child deteriorates or is still ill two days later.

Call 999 if they struggle to breathe, turn blue or grey, are unusually quiet or still, or have a high temperature, the NHS states.

“The more serious bacterial whooping cough produces long paroxysms [sudden attacks] of coughing, followed by a desperate whoop as air is drawn back into the lungs,” Dr Brewer said.

Whopping cough can lead to dehydration, breathing difficulties, pneumonia or seizures in babies under six months, according to the NHS. It is treatable via antibiotics.

Dr Brewer also recommends seeing your GP if a cough is accompanied by chest pain or unexplained weight loss, the result of inhaling poisonous fumes or a foreign substance - like food, or just worries you for whatever reason.