A rheumatologist is a physician who has received extensive training in diagnosing and treating rheumatic conditions. Rheumatic conditions involve the joints, soft tissues, autoimmune system, vascular system, and connective tissues.
Some of the conditions that rheumatologists treat are rheumatoid arthritis, ankylosing spondylitis, gout, sarcoidosis, vasculitis, and lupus. These are all conditions that involve a lot of pain and make mobility difficult. Rheumatologists use medications, such as analgesics, NSAIDs, steroids, DMARDs, infliximab, and adalimumab, as well as occupational therapy, in order to decrease pain and improve a patient's quality of life.

An internist is a physician who focuses on the diagnosis and treatment of conditions that affect the adult population—both acute and chronic.
These doctors are often who adults see as their primary physicians because they treat a broad range of illnesses that do not require surgical or specialist interventions. They also work to help a patient maintain optimal health in order to prevent the onset of disease.
In addition to treating the common cold and flu, internists also treat chronic diseases like diabetes and heart disease.

A family practitioner is a doctor who specializes in caring for people of all ages, at all stages of life. Rather than focusing on the treatment of one disease or patient population, family practitioners are often the doctors that people see for their everyday ailments, like cold and flu or respiratory infections, and health screenings. When necessary, family practitioners will provide referrals for conditions that require the expertise of another specialist.
The doctors may also provide physicals, inoculations, prenatal care, treat chronic diseases, like diabetes and asthma, and provide advice on disease prevention.