If you haven't seen a doctor yet or been diagnosed with asthma, the following four signs are very good indictors that you might have asthma:

• Coughing — sometimes waking you at night.
• Wheezing — a whistling sound during breathing (especially breathing out), which can start as a low whistle and get higher pitched.
• Difficulty breathing — this can include shortness of breath, feeling breathless, gasping for air, difficulty breathing out, or breathing faster than usual. When breathing becomes very difficult, the skin of the chest and neck may suck inward.
• Chest tightness

Even if you have only one of these signs -- like chronic coughing -- it may be due to asthma. These signs can be due to other health conditions -- asthma is not always the cause. Other symptoms, like sweating or rapid heart rate, may be present. Diagnosis can be difficult because symptoms vary from person to person, and even a single individual's symptoms can change over time. In fact, many cases of asthma are misdiagnosed as chronic bronchitis, bronchiolitis, pneumonia, and other illnesses.

The "asthma signs" alone are not enough to diagnose asthma. A doctor must use the proper assessment tests to make the correct diagnosis. One of the key tests is taking spirometry measurements before and after you inhale a bronchodilator. (This indicates whether the airflow obstruction is reversible.)

Once you know or suspect you have asthma, keep track of when the signs appear, as this may help you figure out what is triggering the episodes. Record your signs in a record chart to monitor your asthma on an ongoing basis, as described later.

Early warning signs

When any of the four major signs listed above are getting progressively worse, you may actually be having an asthma episode (asthma attack). However, there are other possible signs that can serve as an early warning that an asthma episode is approaching. These include an itchy neck, dark bags under the eyes, and feeling tired, irritable, or excitable. Other early warning signs are possible and vary by individual.

Danger signs

Call 911 or go to the hospital immediately if any of these danger signs occur:

• Trouble walking or talking because of difficulty breathing
• Hunching over
• Lips or fingernails are blue or gray
• Slow breathing

These are signs of an extreme medical emergency. In the case of children with asthma, the parents, teachers, and other supervising adults should know to look for these signs.