Heart disease is one possible cause of a chronic cough with white phlegm, according to Harvard Medical School. The symptoms also appear with chronic bronchitis, WebMD states. In addition, chronic obstructive pulmonary disease, or COPD, produces a persistent cough accompanied by white mucus, explains Mayo Clinic.
People with heart disease sometimes have a nonproductive cough, reports Harvard Medical School. In other cases, they bring up thin, foamy, white phlegm. Patients often find that their cough worsens when they are lying down.
Chronic bronchitis is characterized by coughing that lasts for at least three months in a row for a minimum of two consecutive years, WebMD says. Additional symptoms of COPD are wheezing, shortness of breath and chest tightness, lists Mayo Clinic. In both diseases, the mucus is white, colorless, yellow or green.