What Is a Sinus Infection?

A sinus infection, also called sinusitis, occurs when the tissue lining the sinuses becomes swollen or inflamed. While healthy sinuses are filled with air, blocked sinuses fill with fluid, which allows germs to grow, resulting in infection. A sinus blockage can be caused by a viral infection, allergies, nasal polyps, or even a eviated septum. (source)

Acute sinusitis usually co-occurs with a cold or other respiratory infection and lasts less than 4 weeks. Chronic sinusitis, on the other hand, lasts for more 12 weeks or is a recurring condition. (source)

Nearly 29 million Americans suffer from chronic sinus infections. (source) Sinusitis Symptoms

Sinusitis is characterized by the following symptoms:

  • Nasal congestion
  • Runny nose
  • Facial pressure or tenderness
  • Postnasal drip
  • Headache
  • Bad breath
  • Sore throat
  • Cough (source)

Is It a Cold or Flu – or Sinusitis?

Both cold and flu viruses enter your body through your nose, eyes, or mouth—that is, your mucous membranes. While a common marker of the flu is a high fever, the flu and the common cold share many similar symptoms, including nasal congestion, fatigue, cough, and sore throat.

Both the common cold and flu can result in sinusitis if your sinuses are blocked, enabling
bacteria to grow.


Most cases are caused by respiratory viruses and occasionally by a bacterial infection. Because viruses cause most cases, antibiotics are not generally used.


  • Cold or allergy symptoms that don’t improve within 14 days
  • Fever (low-grade)
  • Cough that lasts longer than 10 days
  • Coughing up mucus that may be yellow or green
  • Thick, dark mucus coming from the nose
  • Feeling run-down or tired
  • If your symptoms persist.

Treatment Options: Amoxicillin-clavulanate, Cefpodoxime, Levaquin, or Doxycycline