This article reports the case of a 30-year-old female patient who suffered for many years from initially unspecific symptoms, such as recurrent, nonallergic and noninfectious sinusitis, late-onset bronchial asthma and pronounced lymphadenopathy; however, the correct diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA) could only be made by histological investigations after the appearance of skin symptoms. The EGPA is a severe systemic disease which, if left untreated, can cause multiple organ damage and even be fatal. With adequate treatment the disease is mild in more than 90% of cases and patients can even completely recover. By making the correct diagnosis, the patient could be successfully treated and the risk of late manifestations and subsequent damage with a potentially fatal outcome was reduced.