Various inflammatory diseases could be the culprit if your hands are hurting and inflamed. Possible causes include:

Dermatomyositis.Inflammatory bowel disease.Psoriatic arthritis.Rheumatoid arthritis,Dermatomyositis is a rare skin and muscle disease. In addition to joint swelling, it can produce a rash and muscle weakness. Its cause is unknown, but factors like genetics and the environment seem to be involved.Inflammatory bowel disease (IBD) is a term that includes Crohn’s disease and ulcerative colitis. In addition to causing inflammation of the gastrointestinal tract, IBD can cause joint pain and swelling (arthritis) or only joint pain (arthralgia). The pain and swelling are more likely to affect your large joints like your elbows, wrists, knees, ankles, or spine.Psoriatic arthritis is a chronic, inflammatory disease of the joints. The joint swelling is accompanied by dry, red, and flaky skin. You could have relatively few skin lesions but many affected joints. Psoriatic arthritis often shows up from ages 30 to 50 years, usually about 10 years after psoriasis shows up.⁹Rheumatoid arthritis has similar symptoms to psoriatic arthritis but without skin lesions. Instead, it usually appears in the same place on both sides of your body. It can also affect your knees, ankles, elbows, feet, cervical spine, and jaw. Its cause may be a combination of genetic risk factors, environmental factors, and abnormal immune responses.⁸