A 55-year-old man presents with pain in his great toe that began 2 days ago. On physical exam, his first metatarsophalangeal (MTP) joint is red, warm, and tender to palpation (Figure A). His skin is intact with no evidence of ulceration. He reports pain with range of motion. He denies recent fevers and his admission temperature is 37.9°C. Labs are drawn and significant for a WBC of 15K (reference range [rr], 4500-11000 µL), ESR of 90 (rr, 0-20 mm/h), and CRP of 6.5 (rr, 0.08-3.1 mg/L). A radiograph of his foot is shown in Figure B. Which of the following is the next best step?