Asthma is commonly overlooked or misdiagnosed in adults. Adult-onset asthma differs from asthma that first occurs in childhood as it is less well controlled, more. Oct 6, - Asthma is common in childhood, but you can develop it at any point in your life. It's not uncommon for people over the age of 50 to be diagnosed with this lung disorder. Childhood asthma and adult-onset asthma have the same symptoms, and both have similar treatments. This can lead to adult-onset asthma.Symptoms · Similarities · Differences.