More than 90% of sinus infections are caused by viruses and should not be treated with antibiotics, a common practice that can increase bacterial resistance to the drugs, the Infectious Diseases Society of America said in new guidelines.

Nearly one in seven people is diagnosed with a sinus infection each year, and such infections are the fifth-leading reason for antibiotic prescriptions, the IDSA said, but 90% to 98% of cases are caused by viruses, which are not fazed by antibiotics.

"There is no simple test that will easily and quickly determine whether a sinus infection is viral or bacterial, so many physicians prescribe antibiotics 'just in case,'" said Anthony W. Chow, M.D., chair of the guidelines panel.

Read more from the Center for Infectious Disease Research & Policy at the University of Minnesota.