Asthma - Diagnosis
A first step in diagnosis often involves taking a personal and family medical history. These histories can help a doctor determine whether asthma is a likely cause of a patient's problems.
Visual signs can also be used to diagnose asthma. Hunched shoulders and tightened neck muscles indicate that a patient is trying to get more air into his or her lungs. Increased amounts of nasal (nose) secretions are another sign of asthma. Eczema (pronounced EK-suh-muh) and other skin disorders (see skin disorders entry) are a sign that a person may have allergic reactions associated with asthma.
A number of tests can be used to diagnose asthma. A spirometer, for example, measures the rate at which air is exhaled from the lungs and how much air remains in the lungs. The device is used before and after a patient inhales a drug that widens the air passages. It tells whether airway narrowing is reversible, a typical finding with asthma. Patients can be given a similar instrument called a peak flow meter to use at home. The instrument helps them to determine how serious an asthma attack is.
Tests can also be used to determine the conditions that trigger an asthma attack. Skin tests may show any allergens to which a person is sensitive. That allergen may or may not, however, also be the cause of asthma attacks. Blood tests for the presence of antibodies can also be performed. Any antibodies found in the blood may indicate the allergens to which a person is sensitive.
Patients can also be asked to inhale specific allergens to see what effects they have. A spirometer is used to determine whether airways have become narrowed by the allergen. The spirometer is also used after a patient has exercised to see whether exercise-induced asthma is a possibility. A chest X ray can be taken to rule out conditions that produce symptoms similar to those of asthma.