Most sinusitis cases are caused by viruses and resolve without antibiotics. However, if symptoms do not resolve within 10 days, amoxicillin/clavulanate is a reasonable antibiotic association for first treatment. A 2018 Cochrane review, however, found no evidence that people with symptoms lasting seven days or more before consulting their physician are more likely to have bacterial sinusitis as one study found that about 80% of patients have symptoms lasting more than 7 days and another about 70%. Antibiotics are specifically not recommended in those with mild / moderate disease during the first week of infection due to risk of adverse effects, antibiotic resistance, and cost.