Acute diseases differ from chronic diseases in both how suddenly they appear and how long they last. As such, acute diseases have a rapid onset and last for around a couple of days to a couple of weeks. In contrast, the symptoms of a chronic disease appear over a gradual period and last for at least three months. Moreover, acute diseases are often caused by a virus or infection, while chronic illnesses often occur due to unhealthy lifestyles, genetic factors, and aging. That said, many acute illnesses, such as heart attacks or gastrointestinal issues, are also caused by unhealthy habits like poor eating, smoking, or inadequate physical activity.