Silent symptom asthma refers to asthma symptoms that don't make audible noise. The most common silent symptoms of asthma are shortness of breath and tightness in your chest.

Asthma is a condition in which your airways narrow and swell and may produce extra mucus. This can make breathing difficult and trigger coughing, a whistling sound (wheezing) when you breathe out, and shortness of breath. 

According to the American Academy of Allergy, Asthma & Immunology (AAAAI), no evidence wearing a face mask can worsen your asthma.

Chronic asthma often results in scarring of the lung airways (airway fibrosis) and this can cause airway obstruction.

An allergy starts when your immune system mistakes a normally harmless substance for a dangerous invader. The immune system then produces antibodies that remain on the alert for that particular allergen.

Airborne allergens, such as pollen, dust mites, mold spores, pet dander or particles of cockroach waste. Respiratory infections, such as the common cold. Physical activity.

Spirometry. This is the main test doctors generally use to diagnose asthma in people 5 years or older. To help determine how well your lungs are working (pulmonary function), you take a deep breath and forcefully breathe out (exhale) into a tube connected to a spirometer.

A blood test is a quick and simple test that can give useful information about your general health and the type of asthma you have. A blood test can help you and your specialist team know: If you have high levels of allergic antibodies in your blood. This suggests your severe asthma is triggered mainly by allergy.

Asthma can begin at any age, but most children who have it have their first symptom by age 5.

Can you have asthma without knowing? Yes, it is possible to have asthma without knowing it, especially if your symptoms are mild or atypical. If you suspect asthma or any kind of respiratory condition, you should consult a healthcare provider for a proper diagnosis.