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.
1 Calcification of a valve may also result in stenosis. 2  This causes the heart muscle to work harder to push blood through the narrowed opening and possible heart failure. 3  Valve regurgitation (or insufficiency) is a valve that leaks causing blood to pass backward against the normal blood flow pattern in the heart.