What is the primary etiology of erythema multiforme?

Erythema multiforme is primarily characterized by its idiopathic nature, meaning that in many cases, the exact cause remains unknown. While there are known triggers such as infections (particularly herpes simplex virus), medications, and sometimes autoimmune conditions, the classification of most cases falls under idiopathic due to the lack of a definitive underlying etiology in a significant number of presentations.

Understanding this condition involves recognizing that while specific infectious agents or environmental factors can precipitate an episode, they do not account for all cases of erythema multiforme. Therefore, idiopathic is the most fitting classification for the majority of instances. This aligns with clinical observations where patients may develop the condition without any identifiable causes, further supporting the idea that a substantial percentage of cases are idiopathic.