May 29, · Adult-onset asthma is asthma that develops in adulthood. In most cases, people develop asthma during childhood, though it can arise at any age. According to the . Different illnesses, viruses, or infections can be a factor in adult onset asthma. A bad cold or a bout with the flu is often a factor in adult onset asthma. Smoking does not cause adult onset .
When a doctor makes a diagnosis of asthma in people older than age 20, it is known as adult-onset asthma. Among those who may be more likely to get adult-onset asthma are: Women .