Its no fun coping with the stuffy, dripping head congestion of a winter bug. But how do you know if youre fighting a common cold or a sinus infection? "The symptoms can overlap, and it can be hard to tell the difference," says Dr. Ahmad Sedaghat, an otolaryngologist (ear, nose, and throat specialist) with Harvard-affiliated Massachusetts Eye and Ear Infirmary. The common cold More than 200 viruses can cause a common cold. The most common culprits — responsible for up to 40% of colds — come from a family of viruses called rhinoviruses. Cold symptoms typically include a sore throat, nose and sinus congestion, thick and sometimes discolored discharge, a runny nose, and sneezing. You may also develop a cough and hoarseness. Sinusitis The sinuses are a group of air-filled, connected spaces in your skull. They are located between your eyes and behind your nose, cheeks, and forehead. Membranes in the walls of the sinuses produce mucus that catches germs and other pollutants. Tiny hairlike structures called cilia on the sinus walls sweep the mucus out of your sinuses and into your nose. When you have a cold, the virus can infect the sinuses and cause inflammation in the sinus membranes. Thats known as viral sinusitis. The sinuses can also become infected from bacteria. This condition, known as bacterial sinusitis or (in more casual terms) a sinus infection, may need to be treated with antibiotics. In both viral and bacterial sinusitis, the sinus lining swells, blocking mucus from draining. Symptoms include pressure, pain, nasal congestion, thick discolored discharge (yellow or green), a diminished sense of smell, fever, headache, pain in the teeth of the upper jaw, and fatigue. Green discharge and fever may be more likely in bacterial sinusitis, although not all doctors agree on this. Chronic sinusitis An acute sinus infection is temporary. But older adults are prone to chronic sinusitis, often caused when the immune system no longer recognizes bacteria that normally live in the sinuses. "We differentiate the types of sinusitis based on the duration of symptoms, which include blockage in the nose, drainage from the nose, facial pain or pressure, and decreased sense of smell. If you have two of those for at least 12 weeks, you meet clinical criteria for chronic sinusitis," says Dr. Ahmad Sedaghat, an otolaryngologist with Harvard-affiliated Massachusetts Eye and Ear Infirmary. Treatment to manage symptoms includes saltwater nasal rinses, daily nasal steroid sprays, and — in extreme cases — surgery. Detecting the difference There are two primary ways to differentiate a cold or viral sinusitis from a bacterial sinus infection. "One is that the symptoms of a cold or viral sinusitis traditionally begin to improve after three to five days. The symptoms of a bacterial sinus infection tend to dwell, lasting longer than 10 days without improving," says Dr. Sedaghat. "If symptoms of what you thought was a cold last longer than 10 days without improvement, then that may very well be a sinus infection." The other is a pattern of symptoms: an illness thats apparently a cold starts to improve after a few days, but suddenly rebounds and becomes worse. "Thats called double worsening, and suggests that what began as a cold has turned into a bacterial sinus infection," Dr. Sedaghat explains. What you should do Dr. Sedaghat recommends that you treat colds symptomatically. "I tell my patients do whatever makes them feel better. Pain relievers like acetaminophen [Tylenol] and ibuprofen [Advil] can help. Home remedies that can improve nasal symptoms include saltwater rinses for the nose," Dr. Sedaghat suggests. He also points out that maintaining a healthy diet and drinking plenty of fluids can help keep your energy levels up. Sinus infections are treated the same way as a cold. If bacteria cause the infection, antibiotics are an option. But many bacterial sinus infections get better on their own. Should you self-diagnose? This is one scenario where its okay to wait a few days before reporting your symptoms to your doctors office. If symptoms dont improve on their own, you might be dealing with a bacterial infection, not a viral one. Its also a good idea to have your physician make sure your sinus blockage isnt being caused by nasal polyps or (rarely) tumors.(Harvard Health Letter)