For other people, only certain things set them off, such as playing a sport or being around a pet. It depends how often you use it. If you take it perhaps once a week, you're probably okay. But if you are having constant asthma attacks you're going to want to take the steroids. Bottom-line, call your doctor.
Doctors are sometimes hesitant to prescribe steroids because of the side effects.
Prolonged steroid use has been linked to side effects including osteoporosis and cataracts, which is why doctors try and prescribe the lowest dose possible and also try not to keep a patient on them for too long. In fact, many asthmatics will take steroids for say 3 months, then stop taking them, and then go back to taking them. But if you are at risk for say osteoporosis, you can take calcium supplements and exercise to counteract the effects of the steroids. You have to stay away from things that may trigger an attack. For some people, that is the dander from a cat or an animal.