Common causes of swelling inside the ear include acute otitis externa, acute otitis media, and eczema of the external ear canal. 1. Acute otitis externa: Acute otitis externa is easily caused by incorrect ear pulling and repeated water ingress in the ear. When the inflammation symptoms are severe, the external ear canal will become swollen and congested, which may even cause ear stuffiness, ear blockage and hearing loss. 2. Acute otitis media: due to bacterial or viral infection, can be secondary to colds or respiratory tract infectious diseases. Inflammation can lead to congestion, edema and suppuration of the middle ear mucosa, and pus outflow after perforation of the eardrum can stimulate redness and swelling of the skin of the external auditory canal. 3. Eczema of the external auditory canal: it is often related to allergic reactions, mental factors, neurological dysfunction, endocrine disorders, metabolic disorders, dyspepsia and so on. Examination can see redness and swelling of the skin of the outer ear, scattered erythema, small corn-grain papules and small translucent blisters. Swelling inside the ear can be caused by different reasons, so when this phenomenon occurs, it is recommended to consult a doctor in time, clear diagnosis and targeted treatment.