Allergic Granulomatous Angiitis is a rare condition that causes blood vessel inflammation, typically in the nose, lungs, and kidneys. This condition is commonly known as Churg-Strauss syndrome, after the two doctors who first described it in the 1950s. Another potential synonym for Allergic Granulomatous Angiitis is eosinophilic granulomatosis with polyangiitis (EGPA), which reflects the fact that the condition involves granulomas (inflammatory nodules) and polyangiitis (inflammation of multiple types of blood vessels). Another possible synonym is allergic vasculitis, which highlights the role of allergic reactions in the development of blood vessel inflammation. Regardless of the terminology used, prompt and accurate diagnosis is essential for effective treatment of this potentially serious condition.