Stridor and noisy breathing: causes, red flags and when to seek help

Stridor is produced by turbulent airflow past a narrowing in the voice box, windpipe or throat. It is typically loudest when breathing in and has a harsh, musical, crowing or raspy quality that is often heard without a stethoscope. Wheeze, in contrast, is a whistling sound mainly when breathing out and comes from narrowed airways deep in the chest, as in asthma.

Because the narrowing is high in the airway, there is little room to spare. A small amount of swelling can make a large difference to airflow, which is why stridor in a young child, whose airway is narrow, can get worse quickly.

The NHS describes croup as a common condition that mainly affects babies and young children, usually mild, with symptoms that include a barking cough that may sound like a seal, a hoarse voice, difficulty breathing and a high-pitched, rasping sound when breathing in. Cold-like symptoms such as a temperature, runny nose and cough usually come first, and croup often gets worse at night. It says a child with mild croup usually improves within 48 hours, and advises sitting the child upright, keeping them calm because crying makes symptoms worse, giving plenty of fluids, checking on them regularly including at night, and giving paracetamol or ibuprofen for fever or discomfort. It says not to put the child in a steamy room or get them to inhale steam.

The NHS says to ask for an urgent GP appointment or call NHS 111 if you think your child may have croup, since the doctor may give medicine to shorten the illness. Other causes in infants include a floppy larynx present from birth, which tends to be noisy but thrive normally, bronchiolitis, which the NHS associates with cold-like symptoms, wheezing, rapid breathing and not feeding, and an inhaled object.

Stridor in an adult is uncommon and always warrants prompt assessment. Causes include swelling from an allergic reaction, infection of the epiglottis, an inhaled or swallowed object, a vocal cord that is paralysed or not moving, scarring or narrowing of the windpipe after a breathing tube or tracheostomy, injury to the throat, and growths in the voice box, thyroid or neck compressing the airway.

The NHS laryngeal cancer page lists shortness of breath or difficulty breathing among its most common symptoms, together with a hoarse or changed voice, a lump in the neck and difficulty or pain swallowing, and advises contacting NHS 111 for difficulty breathing and calling 999 or A&E for severe difficulty breathing where you are gasping, choking or unable to get words out.

For croup the NHS says to call 999 or go to A&E if your child is struggling to breathe (you may notice grunting noises, the tummy sucking under the ribcage, or breathing that sounds different), has blue, grey, pale or blotchy skin, lips or tongue, is sleepier than normal or difficult to wake, is unusually quiet and still, is limp, floppy or not responding like they normally do, is very upset or restless and cannot be calmed down, or is unwell and drooling more than normal, finding it hard to swallow or wanting to sit rather than lie down.

For epiglottitis, the NHS says the main symptom is finding it very difficult to breathe, usually coming on quickly, with breathing that may be very fast or slow, easier when you lean forward and make a high-pitched, rasping sound on breathing in. A child may not want to lie down and will lean forward with the neck pushed out. Other symptoms include a very sore throat, high temperature, hoarse voice, painful and difficult swallowing, drooling, pale, grey or blue-tinged skin, and being extremely tired or very restless and irritable. Call 999, stay upright, and do not drive yourself.

For anaphylaxis the NHS says call 999 if the lips, mouth, throat or tongue suddenly become swollen, you are breathing very fast or struggling to breathe, the throat feels tight or you are struggling to swallow, skin, tongue or lips turn blue, grey or pale, you suddenly become very confused, drowsy or dizzy, or someone faints and cannot be woken. Use an adrenaline auto-injector if one is available.

Do not examine the throat with a spoon or try to make a child with suspected epiglottitis lie down or open their mouth, since this can worsen obstruction.

The priority is the airway, not the diagnosis. Staff will watch the breathing effort, oxygen level, colour and alertness, and keep the person calm and upright. Oxygen is given if needed. In croup, a single dose of steroid medicine is typically given. In suspected epiglottitis, the NHS says treatment is in hospital, with oxygen, sometimes a breathing tube or tracheostomy, and antibiotics through a vein, with tests such as laryngoscopy, throat swab, blood tests, X-ray or CT.

Once the airway is safe, an ear, nose and throat specialist may examine the voice box with a flexible camera, and scans or lung function tests are used for longer-term narrowing.

The NHS says the most common cause of epiglottitis is Haemophilus influenzae type b (Hib), that the 6-in-1 vaccine in the NHS schedule protects against Hib in four doses at 8 weeks, 12 weeks, 16 weeks and 18 months, and that not smoking reduces the chance of epiglottitis. For anyone with a known severe allergy, carrying and knowing how to use adrenaline auto-injectors is the key preventive step. Never leave small children alone with small objects that can be inhaled.