An 78-year-old woman has had diffuse aching of her shoulders and a bitemporal headache for the past 5 months. BMI is 35. Vitals are within normal limits. The distal interphalangeal joints of both hands show mild deformity. Range of motion is full. There is no edema or erythema of her joints. Neurologic examination is normal. ESR is elevated. Which of the following is the most likely diagnosis?
Fibromyalgia
Polymyalgia rheumatica
Polymyositis
Psoriatic arthritis
Rheumatoid arthritis
