I don't know if I'd describe it as a flair, but my A.S. and inflamation in general is worse during allergy season, illness, or low air pressure events.

Oddly enough, I've noticed certain drugs like over the counter sleep aids can also trigger my hip, shoulder, and chest pain/arth

Diagnosed with A.S., DDD, scoliosis, sleep apnea -- Tested positive for HLA-B27 gene; family history; visible damage on x-ray; significant iritis; enthesitis inflammation; fatigue; feverish; peripheral arthritis; Osteopenia; heart, G.I., and skin symptoms - :: - Insidious and often disabling pain started in my teens & 20's with heel pain; chest pain and hip-buttock in my early 20's; low back pain in my late 20's; mid thoracic and cervical in my 30's. Biologics in my 40's. (On remicade)