No content from the article "Periumbilical Erythema Migrans" from the New England Journal of Medicine (Volume 394, Issue 1, January 1, 2026) is available in the provided search results. The search results contain only the title, a short translation, and references to other topics such as contact dermatitis or infectious diseases[1][2][3]. Without verified facts from the article, it is not possible to create a summary.