Medically reviewed guide · Last updated: 1 August 2026 · Reading time: approx. 8 min

Wheezing: Asthma, COPD or Something Else?

The most common causes compared

The causes in detail

The whistling is not a condition in its own right but an acoustic clue: somewhere between the windpipe and the small bronchi, the path for the air has become too narrow. What lies behind it is often given away by the pattern alone.

Asthma: in attacks, at night, with recognisable triggers

In asthma the bronchi react over-sensitively: the lining swells, the muscle goes into spasm, and thick mucus is added to the mix. What is typical is the attack-like course — between the episodes many people feel completely well.

Two patterns give it away. The time of day: symptoms cluster at night and in the early morning. And the triggers: cold air, exertion, pollen, dust mites, animal dander, smoke or an infection. A dry cough, tightness in the chest and shortness of breath usually come with it. There is also a special form with nothing but a cough — so the absence of a wheeze does not rule asthma out.

COPD: creeping, worst in the morning, almost always with a smoking history

COPD develops over years: permanently inflamed, narrowed airways. Unlike in asthma, the wheezing rarely disappears altogether. The typical picture is someone past 40, a smoker or ex-smoker, who coughs in the morning, brings up thick phlegm and has become slower on the stairs — often without noticing it. Asthma and COPD can exist side by side; the distinction is not made by the ear but by lung function testing.

Acute bronchitis: the wheeze with an expiry date

In acute bronchitis the lining of the bronchi becomes inflamed, usually because of viruses. The swelling narrows the airways temporarily — which is why people who have neither asthma nor COPD can wheeze as well. What is characteristic is the time course: first a scratchy throat and a blocked nose, then a cough, then over days to weeks a rattling and wheezing that gradually disappears — how to tell it apart from flu and COVID is set out in the guide Cold, flu or COVID. If the wheezing lasts longer than three to four weeks, unrecognised asthma should be considered.

Heart failure: “cardiac asthma”

When the heart no longer pumps enough blood onward, fluid backs up into the lungs, the lining of the small airways swells — and it whistles. This used to be called “cardiac asthma”: it sounds like asthma but has a different cause. In heart failure, however, moist crackles are usually to the fore rather than a dry wheeze. On top of that come signs that are absent in asthma: breathlessness when lying down, waking at night with a start, and fluid retention in the lower legs that is worst in the evening. Several kilograms of weight gain within a few days is retained water.

Allergies: the trigger behind the trigger

Allergic rhinitis — hay fever in everyday language — is often the forerunner and the companion of allergic asthma: what irritates the nose often irritates the bronchi too. If your wheezing appears seasonally, or together with itchy eyes and bouts of sneezing, allergy testing belongs in the assessment.

Foreign bodies, vocal cords and rarer causes

In toddlers, sudden, often one-sided wheezing out of the blue — particularly after a coughing or choking episode while playing or eating — is an inhaled foreign body until proven otherwise. That is an emergency, even if the child has calmed down in the meantime. In adults the vocal cords can also close paradoxically on breathing in: a high-pitched sound that gets mistaken for asthma but does not respond to asthma inhalers.

Wheeze or stridor? The most important distinction

If you remember only one point from this article, make it this one: two breathing sounds that sound similar to the lay ear mean very different things.

Self-tests: first clues at home

These observations do not replace a diagnosis. They do, however, help you make the conversation at your practice more precise.

• The in-or-out test: do I hear the sound when the air goes in, or when it goes out? Breathing out points to a wheeze, breathing in to a stridor. Record it on your phone if need be and play it back at your appointment.
• The time-of-day and trigger test: note down over two weeks when it whistles and what came before. At night and early in the morning points more to asthma, in the morning with phlegm more to COPD, lying down with breathlessness more to a heart problem.
• Peak flow measurement: a peak flow meter measures how fast you can breathe out. Measure morning and evening standing up, three attempts, and note the best reading. What is interesting is not the single number but the variation: if the morning and evening readings are clearly far apart, that points to asthma. Which readings are green, amber and red for you is set by your practice.
• The exertion and speech test: how many flights of stairs can you manage without a break — and what was that like a year ago? In an acute episode, can you speak in whole sentences or only in single words? The simplest assessment of severity there is.

Warning signs: when not to wait

• Breathlessness already at rest or when speaking
• Being able to speak only in single words rather than in whole sentences
• Lips, tongue or fingertips turning blue
• Sudden wheezing after an insect sting, a medicine or a meal
• Visible drawing-in between the ribs, particularly in children
• Confusion, marked restlessness or increasing drowsiness
• Your reliever inhaler no longer works, or only very briefly
• Wheezing with fever, chest pain or blood in your phlegm

The treatment pathway: step by step

Things are usually approached in stages — first make sense of it, then measure, then treat in a targeted way. The treatment decision always rests with the practice treating you.

1. Observe and document. Two weeks of notes on timing, triggers, accompanying symptoms and medicines are the basis of every good first consultation.
2. See your GP. Listening to your chest, blood pressure, oxygen saturation and a thorough conversation clear up a great deal. Bring your complete medication list — including over-the-counter products.
3. Lung function test. If the reading improves markedly after an airway-widening inhaler, that points to asthma; if the narrowing stays, more towards COPD.
4. Further investigation as suspected. Allergy testing, a chest X-ray, blood tests, and a cardiology assessment if a heart problem is suspected.
5. Settle on treatment and practise the technique. Anyone who is given an inhaler device should demonstrate how they use it at the practice or the pharmacy.
6. Arrange a review. After four to eight weeks, check: the peak flow trend, how often the reliever inhaler was used, night-time symptoms, exercise capacity.

The medication angle: when the wheeze comes out of the tablet box

Some active ingredients narrow the bronchi directly, others set off a reaction — and others again do not work because they never arrive where they are supposed to.

Beta blockers: they do not only act on the heart

Beta blockers block certain docking sites. Closely related docking sites also sit in the muscle of the bronchi — if those are blocked, the airways can narrow and set off wheezing in people with asthma. So-called selective beta blockers such as metoprolol and bisoprolol target the heart preferentially. That expressly does not mean they are free of risk: the selectivity is relative and decreases as the dose goes up. In known asthma they are therefore weighed up carefully and started at a low dose.

Aspirin and NSAIDs: the triad hardly anyone knows about

There is a condition made up of three building blocks that is recognised far too rarely: asthma, nasal polyps and an intolerance of aspirin or other anti-inflammatory painkillers — often called Samter’s triad or aspirin intolerance in everyday use.

What makes it special: it is not a classic allergy but a metabolic reaction. The active ingredients block an enzyme pathway, which makes the body produce more inflammatory messenger substances — and those narrow the bronchi. People affected therefore usually react to the whole drug group: aspirin as much as ibuprofen. Typical features are a runny nose, an urge to sneeze, facial flushing and wheezing within minutes to hours of taking it. Anyone with a blocked nose, recurring nasal polyps and asthma should raise it — the diagnosis changes the choice of painkiller for good.

ACE inhibitors: cough yes, wheeze no

A common misunderstanding: ramipril and other ACE inhibitors cause a persistent dry, irritating cough in some of the people who take them — without phlegm, without fever, often only weeks to months after starting treatment. That cough is a nuisance, but it is not a wheeze. Anyone who gets an asthma inhaler prescribed for it is treating the wrong problem. Conversely, it is worth raising the cause — there are alternatives, and the decision is made by the practice treating you.

Inhaler technique: the most common reason for “the inhaler is not working”

If salbutamol, budesonide or tiotropium do not work as expected, the reason is surprisingly often not the active ingredient but the way it is used: studies regularly show that a considerable proportion of users make at least one relevant mistake — and then a large part of the dose ends up in the mouth instead of in the lungs. Common ones are: not breathing out first, breathing in too hastily, not synchronising actuation and inhalation, not holding the breath. The guide Inhaling correctly goes through the steps for each type of device.

How to prevent wheezing

• Stopping smoking — the single most effective step — in COPD it slows the loss of lung function, in asthma it improves control. Passive smoking and e-cigarettes count too.
• Know your triggers and reduce them — mite-proof covers for the mattress, airing the room after the pollen peak rather than during it, a scarf over mouth and nose in the cold.
• Keep your preventer treatment going, even on good days — anti-inflammatory inhalers work preventively. Stopping them because things are going well at the moment is the most common reason for the next flare-up.
• Always have your reliever inhaler with you — handbag, rucksack, sports bag, and once a quarter check the expiry date and how full it is.
• Movement rather than taking it easy, with an eye on peak flow — if you know your own readings, you spot a deterioration early.

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