Lupus
Systemic lupus erythematosus (SLE or lupus) is a chronic autoimmune disease that can be fatal, though with recent medical advances, fatalities are becoming increasingly rare. SLE is one of several diseases known as “the great imitators” because its symptoms vary so widely, it often mimics or is mistaken for other illnesses and because the symptoms come and go unpredictably. Common initial and chronic complaints are fever, malaise, joint pains, myalgias, and fatigue. As lupus erythematosus is a chronic disease with no known cure, treatment is restricted to dealing with the symptoms. Essentially, this involves preventing flares and reducing their severity and duration when they occur. There are several means of preventing and dealing with flares, including drugs, alternative medicine, and lifestyle changes.
Source: wikipedia.org