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.
Aortic valve regurgitation is a condition in which the heart's aortic valve does not close properly. This allows blood to leak backward from the aorta into the left ventricle. The condition can be caused by several things, and over time may lead to symptoms such as chest pain, shortness of breath, heart failure, and fainting.