I also suffer with anorexia as a symptom of a flare. For the last few weeks I've literally been forcing myself to eat at least once a day, but I have no real appetite. Actually, I didn't eat at all today. Although I could sure stand to lose a bunch of weight, I haven't lsot an ounce. It seems my body has slipped into starvation mode. Weight loss and lack of appetite are most definitely symptoms of a flare and you are right to be concerned about
Like you, I also have Spondyloarthropathy, the Crohn's-related inflammatory arthritis. My Rheumatologist the is the one who prescibes Humira for me to treat the arthritis and I get the benefit of it treating my CD too. Often my joint problems are worse than my gut, even when my gut is flaring.
The best thing you can do is to try eating small meals a few times a day. Just a little snack 5 or 6 times a day might work for you. It's important that you get enough protein. Try crackers with peanut butter, a bowl of cereal, a smoothie with protein powder - anything in small amounts that you can tolerate. I know I should be doing this myself, but my joints are so bad I've mostly been laying in bed. Yesterday I could barely even walk.
I hope you find whatever works for you.
Keah, who still does not have Crohn's!!!