You may have heard some buzz about Lupus recently, thanks to celebs like Selena Gomez opening up about what it's like to live with the condition. But while the word “lupus” (short for systemic lupus erythematosus, or SLE) has appeared in recent headlines, there’s a good chance you still don’t know too much about the disease. For example, were you aware that 1.5 million Americans have it? Or that it’s actually an autoimmune disease that can harm the skin, kidneys, heart, nervous system, blood cells, and other parts of the body, depending on its severity? It can also result in a range of symptoms, including fatigue, joint pain, swelling, rashes, and fever. Because of these varied symptoms, it can take years to properly diagnose lupus. There isn't one lab test for the condition, and it’s commonly confused with other conditions like rheumatoid arthritis or fibromyalgia. There's no question it’s a complicated disease, for both doctors and the rest of us to understand. To get a better sense of lupus, watch the video above.