Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare ANCA-associated vasculitis characterized by asthma, eosinophilia, and multisystem involvement. Early phases often mimic isolated allergic or respiratory disorders, leading to delayed diagnosis in primary care. Recognizing “red flags” in patients with persistent eosinophilia and atypical asthma is essential to prevent organ damage.A 51-year-old woman presented with a three-year history of progressively evolving symptoms. The first episode was generalized urticaria after outdoor work, requiring hospitalization. Eighteen months later, she developed persistent cough and was diagnosed with IgE-mediated asthma. Despite therapy, exacerbations persisted, starting with nasal congestion, postnasal drip, and “nasal” voice, followed by dyspnea and non-productive cough. During the last year, intermittent petechiae appeared and resolved spontaneously. Her history included chronic pansinusitis and seasonal allergic rhinitis. Family history was significant, as her sister had granulomatous vasculitis. Laboratory evaluation revealed persistent eosinophilia (up to 60%). The final diagnosis was eosinophilic granulomatosis with polyangiitis, chronic course, with pulmonary involvement, pansinusitis, and cutaneous manifestations.This case demonstrates the classical phased evolution of EGPA: allergic manifestations → asthma → systemic vasculitic signs. The combination of recurrent urticaria, intermittent petechiae, chronic rhinosinusitis, eosinophilia, and family history highlights early diagnostic clues often overlooked in primary care.Persistent eosinophilia in asthma should prompt evaluation for systemic vasculitis. Recurrent skin lesions, chronic rhinosinusitis, suboptimal asthma control, and positive family history are “red flags.” Early recognition and specialist referral can prevent organ damage and improve outcomes.EGPA often presents initially with isolated allergic or respiratory symptoms, delaying diagnosis. Recognizing symptom clusters, including eosinophilia, skin manifestations, and rhinosinusitis, allows earlier detection. Awareness of the classical phased evolution aids primary care physicians in timely referral.Heightened suspicion for EGPA in patients with asthma, persistent eosinophilia, and recurrent cutaneous or sinonasal manifestations enables early diagnosis, specialist referral, and improved prognosis.