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.
Tricuspid regurgitation is a disorder in which the heart's tricuspid valve does not close properly, causing blood to flow backward (leak) into the right upper heart chamber (atrium) when the right lower heart chamber (ventricle) contracts.News & Features.he most common cause of tricuspid regurgitation is enlargement of the right ventricle, which pumps blood to the lungs, where it picks up oxygen. This enlargement may be a complication of any disorder that causes extra strain on the right ventricle.