My asthma has also come and gone. It's allergy induced, and I also can't remember the last time I took my inhaler. However, when I started riding, I would take it before a ride, if it was very hot and humid. I have built up my tolerance for that, a great deal. If I am already having a bad time with allergies, or I am sick, I rest instead of riding, or I take a walk. I have learned the hard way when not to work through feeling sick, as in avoiding bronchitis or pneumonia.
Take your inhaler. I would hate to not be able to breathe while climbing.
2015 Trek Silque SSL
Specialized Oura
2011 Guru Praemio
Specialized Oura
2017 Specialized Ariel Sport