When you have rheumatoid arthritis (RA), you usually have symptoms like join pain, stiffness, or swelling. But lots of other conditions share similar warning signs. It's sometimes hard to tell whether you have RA or something else.Lyme DiseaseYou get Lyme disease from a tick bite. Bacteria from an infected tick can lead to symptoms that include fatigue, headaches, a fever, or rash.Without treatment, Lyme disease can spread after several weeks to your joints, nervous system, or heart. Most often, it affects your joints. Around 60% of people with Lyme disease get arthritis unless they take antibiotics. Joint issues caused by Lyme disease usually happen in your knees. But RA often shows up first in the smaller joints in your hands and feet. It may spread to larger joints later on."Lyme arthritis" usually heals after 30 days on antibiotic pills like amoxicillin or doxycycline. If not, your doctor may give you antibiotics through an IV. But 10% of people with arthritis from Lyme disease don...