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.
Watch an animation of mitral valve regurgitation. A leaking mitral valve allows blood to flow in two directions during the contraction. Some blood flows from the ventricle through the aortic valve â as it should â and some blood flows back into the atrium.f regurgitation is severe enough, the forward flow of blood is reduced enough to cause heart failure (when the heart does not pump enough blood to the body) which may produce also symptoms ranging from shortness of breath during exertion, coughing, congestion around the heart and lungs, swelling of the legs and feet.