This case highlights eosinophilic granulomatosis with polyangiitis (EGPA) as a rare condition often presenting with asthma and eosinophilia. A 20-year-old female developed Loeffler endocarditis and was treated with methylprednisolone sodium succinate, low molecular weight heparin, and mycophenolate mofetil. Her condition improved, and follow-up showed stable recovery with symptom resolution and better cardiac function.