Treatment may depend on the cause. A sinus infection, also known as sinusitis or rhinosinusitis, occurs when your nasal cavities become swollen and inflamed. Fluid buildup in the sinuses can allow ...

Sinusitis, or a sinus infection, can cause a stuffy or runny nose, a decreased sense of smell, and other symptoms. You can usually manage the symptoms at home with a decongestant. The sinuses are ...