Can sarcoid flare up again after 2yrs

I was diagnosed with grade 1 sarcoid in 2006. I had many symptoms at the time but didnt know it til i went to the dr about raised red lumps on my shins and he sent me for a chest xray. The other symptoms i had were the annoying cough, shortness of breath and incredible pain from my lower back down to my feet-i woke up one day with severe arthritis in my ankles-i couldnt walk! Anyway i wasn't given steroids as it was only grade 1 and was told it would burn itself out which i think it did? The past few weeks i appear to have had mild symptoms and i was wondering if anyone has had a flare up and what could cause this..which is probably a stupid question as no one seems to know what causes sarcoid in the first place! Im not concerned if it has returned just curious. Thanks in advance.