Hello -- I don't have Crohn's -- However, my husband does and that is why I am on this forum. He was taking Humira and developed severe joint pain. He will be seeing my rheumatologist this week -- he is seeing mine because I have Lupus and the reason I am sending this post is that one of the symptoms of Lupus is hair loss. Please realize the hair loss occurs at least 3 to 4 months after the onset of a lupus flare. (it takes that long for the new hair growth to push the dead hair out) So think backward and see if your joint pain started at the same time. You can also test negative for the standard ANA since by the time you are tested the flare may be past you -- but you still may have lupus caused by the Humira. Please check with your rheumatologist -- hair loss is a symptom of Lupus!
I never had the traditional facial rash that most associate with Lupus -- I had low platelet counts, swollen glands and severe joint pain -- add the hair loss to that and I was diagnosed with Lupus -- even though my ANA was negative during my first blood work. The ANA was positive the 2nd time I was tested. It is important to have a urine test too as Lupus can mess with your kidneys. If you have to urinate in the middle of the night every night and it isn't that much urine and you wonder why your body is telling you to get up -- you are not getting old! It is a sign of kidney issues -- tell your rheumatologist if that is happening and he will check for protein and blood in your urine and your creatinine level.
I realize everyone is different -- but Lupus is very difficult to diagnose and you may not be mentioning all of your symptoms to the correct doctor.