Well I respectfully disagree with Nawlinscate that a flare lasts for one day. I believe we have bad days occasionally usually from eating the wrong thing or not enough rest. But a true flare is something that takes more drastic measures to get undercontrol. You have an increase in symptoms i.e. more d, joint pain, fatigue and general feelings of unwellness. I always allow myself to go at least a week before I call the doc, just to make sure that its not just a bug I picked up, or something in my diet not agreeing with me. If it continues more than a week and continues to get worse, then I know its a Crohns flare.
We Crohnies will always have a bad day here and there, but when it lasts for a more prolonged time frame, I believe that is what you can consider a flare.
Been living with Crohn's Disease for 33 years. Currently on Asacol, Prilosec, Estrace, Prinivil, Diltiazem, Percoset prn for pain, Zofran, Phenergan, Probiotics, and Calcium. Resections in 2002 and 2005. Also diagnosed with Fibromyalgia and Osteoarthritis. Currently my Crohns is in remission.