Erythema multiforme (EM) is a skin reaction that comes from an infection or another trigger. EM is a type of allergic reaction. In most cases, it occurs in response to an infection. In rare cases, it is caused by certain medicines or body-wide (systemic) illness. Infections that may lead to EM include:
The most common causes of sudden (acute) aortic valve regurgitation include: 1  Endocarditis, which is an infection in the heart. 2  Aortic dissection, which means that the inner layer of the aorta separates from the middle layer. 3  Problems with a replacement (artificial) aortic valve.  Trauma to the heart valve or aorta.
Definition. Aortic valve regurgitation â or aortic regurgitation â is a condition that occurs when your heart's aortic valve doesn't close tightly. Aortic valve regurgitation allows some of the blood that was just pumped out of your heart's main pumping chamber (left ventricle) to leak back into it.efinition. Aortic valve regurgitation â or aortic regurgitation â is a condition that occurs when your heart's aortic valve doesn't close tightly. Aortic valve regurgitation allows some of the blood that was just pumped out of your heart's main pumping chamber (left ventricle) to leak back into it.