How long does an earache due to sinus congestion last without antibiotics?

Viral infection: Good question. But sinus infection or congestion of the paranasal sinuses does not cause ear infections. They may be related in that the cause of the paranasal sinus infection (assuming it is not nasal allergy) and the middle ear may be infected by the same virus. 98% of upper respiratory infections are viral and no antibiotic is indicated for a minimum of a week and a maximum of 10 days.