Dreaming of asthma means your relaxed state is being attacked by sudden changes. An asthma attack can occur at any given time without warning, as a certain unforeseeable event can be disastrous for your career. Be aware of your current surrounding and don’t let anything unfamiliar trip you up.
Also, having asthma in a dream is a good indication for you to take up meditation to learn how to calm your nerves when dealing with tough life issues.