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Signs of Asthma

Wheezing is a whistling or squeaky sound in your chest when you breathe, especially when you exhale. It is one of the telltale signs of asthma.


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Swelling or narrowing of your throat or the airways to your lungs can cause wheezing. It can also result in shortness of breath, because your lungs can’t hold as much air when they are affected by swelling or mucus buildup.

Although asthma and chronic obstructive pulmonary disease are most often associated with wheezing, an allergic reaction is another common cause of these symptoms.

Sometimes children experience wheezing, but it is not always a sign of asthma. A lung infection can create wheezing in children younger than 5. And wheezing and shortness of breath can sometimes be symptoms of a cold in children with a family history of allergies.  

Wheezing is often, but not always, related to an asthma attack. During an asthma attack, the airways become more narrow. At first, the person wheezes when breathing out, but as the attack gets worse, the wheezing might happen when breathing in. During a severe asthma attack, there might not be any wheezing because not enough air is moving through the airways.


Asthma symptoms like shortness of breath are often closely linked to allergies and exposure to allergic triggers, such as ragweed, pollen, animal dander or dust mites. Irritants in the air like smoke, chemical fumes, strong odors or extreme weather conditions can also be triggers. Sometimes exercise or an illness — particularly an illness that affects your breathing like flu or bronchitis — can bring on asthma symptoms. In addition, if you start wheezing or coughing during exercise, or if physical exertion makes it difficult for you to breathe, you may have exercise-induced bronchoconstriction, or EIB. This is also known as exercise-induced asthma.

Emotions can also affect the way people breath. Physical actions like crying, laughing or shouting can trigger your asthma. Trying to relax and follow a set of instructions is helpful in handling an asthma attack, but panic can make it worse. The rapid breathing that often comes with strong emotions can narrow your airways even more.

Pregnancy can be a trigger for women with asthma in several ways. Hormonal changes that happen during pregnancy can affect the nose and sinuses, as well as the lungs. An increase in estrogen contributes to clogging of the tiny blood vessels in the lining of the nose, which in turn leads to a stuffy nose, especially in the third trimester. A rise in progesterone can also cause shortness of breath. These events may be confused with or add to allergic or other asthma triggers.

Learn about common allergy triggers that can contribute to asthma symptoms and how to avoid them:

How to Get Tested

Allergists are specialists in diagnosing and treating asthma and other allergic diseases. And allergists are specially trained to identify the factors that trigger asthma or allergies.

Asthma is sometimes hard to diagnose because it can look like other breathing problems, such as emphysema, bronchitis and lower respiratory infections. Some people with asthma do not realize they have it and are never treated. Sometimes the only symptom is a chronic cough, especially at night. In other cases, coughing or wheezing may occur only with exercise. Some people mistakenly think they have frequent bronchitis, since respiratory infections usually settle in the chest of people with asthma.

To diagnose asthma and distinguish it from other lung issues, allergists rely on the combination of a medical history and a thorough physical examination, including certain tests. The tests include spirometry (using an instrument that measures the air taken into and out of the lungs), peak flow monitoring (another measure of lung function), chest X-rays, and sometimes blood and allergy tests. 

When to See an Allergist

See an allergist if you develop unexplained wheezing that keeps coming back or along with other symptoms, such as rapid breathing or problems taking in air.

If you begin wheezing after being stung by an insect, taking medication or eating something you are allergic to, then get emergency treatment. You should also seek emergency treatment if you have difficulty breathing or your skin turns blue.

If you have mild wheezing that comes with a cold or an upper respiratory infection, you might not need treatment.

It Could Also Be…

Other conditions — some related to allergies and asthma and some not — can lead to wheezing. If your allergist rules out allergies or asthma, ask what else might be causing your wheezing, such as:

  • Anaphylaxis (a severe allergic reaction, such as to an insect bite, food or medication)
  • Bronchitis
  • Emphysema
  • Inhaling a foreign object
  • GERD (gastroesophageal reflux disease)
  • Medications, particularly aspirin
  • Pneumonia
  • Respiratory syncytial virus (RSV) — especially in young children
  • Respiratory tract infection — especially in children younger than 2
  • Smoking
  • Tumors
  • Vocal cord dysfunction (a condition that affects vocal cord movement)

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