Asthma is normally diagnosed in childhood. For many people, the symptoms will go away or reduce significantly after puberty. After the age of 20, symptoms can return. Researchers have studied reoccurring asthma and have found that people diagnosed with asthma in their childhood will experience symptoms in their 30s and 40s. If you have been diagnosed with asthma and you believe it is inactive, you should try to avoid the triggers that cause asthma attacks. Keep your medications up-to-date and make sure that you have them readily available.