Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare autoimmune condition that causes inflammation of blood vessels, leading to damage in various organs. It is characterized by the presence of high levels of eosinophils, a type of white blood cell, and can affect the lungs, skin, kidneys, and nerves. Symptoms may include asthma, sinusitis, and skin rashes. The exact cause of EGPA is unknown, but it is believed to involve an abnormal immune response. Diagnosis typically involves blood tests, imaging studies, and sometimes a biopsy. Treatment often includes corticosteroids and other immunosuppressive medications to reduce inflammation and manage symptoms.