As such, sinus infection is not known to cause serious complications but in some cases, it can be life-threatening. Depending on the type of sinus infection, the intensity and severity of this infection can be estimated. If someone is suffering from acute infection, the condition may last for 4 weeks or less and is accompanied by discomfort and pain. In case, the infection is not treated within time, the acute stage can advance to further stages called sub-acute and chronic stages. The sub-acute stage lasts between 4 to 8 weeks while the chronic stage can last for 8 weeks or more. In all the three stages of this infection, there is a difference in the severity of the symptoms affecting the patient. Symptoms aggravate from the initial stage (acute) to further stages that are sub-acute and chronic. It is the chronic stage that is considered to be the most dangerous. What is a Sinus Infection? Given the complexity of our biology, the possibility of any minor medical ailment turning out to be deadly for the body can't be denied. However, in case of sinus infection, this rarely occurs. Sinus is generally preceded by a cold flu or common cold. If you're suffering from cold, you're at a higher risk of developing sinusitis, as cold may lead to inflammation and swelling in the sinus area. Symptoms of common cold like post-nasal drip, nasal congestion and runny nose may often cause swelling in the sinus areas i.e., the air filled cavities spread all across the face. The presence of sinus cavities in the forehead and also on each side of the nose, extending to several inches in the head and face area causes pain in many areas of the head. Sinus cavities have a name for the bone in which they are located. The names of these cavities are as follows: Maxillary (cheek), Ethmoid (between the eyes), Frontal (forehead) and Sphenoid (middle of the skull). Due to common cold, there is a swelling in the sinus area obstructing the overflow of mucus. This mucus that stays in the normally air filled sinus is infected due to bacterial or viral growth causing sinus infection. Can Sinus Infection be a Life-threatening Disease? The dilemma that sinus brings along with it is that the symptoms of common cold and sinus often overlap. Sinusitis symptoms are generally cited to be the presence of thick, yellow and foul-smelling nasal discharge. Besides that, pressure in the head or pain around the face and eyes, nasal congestion, recurring cold and fever and cough are also some commonly observed symptoms of sinus. These are very often the symptoms of common cold. However, the difference that must be observed while understanding if there is a possibility of sinusitis is the nasal discharge time period and the painful feeling around the eyes and face. In case, there is a continuous thick and foul-smelling nasal discharge along with pain in the eyes and face for more than a week, the possibility of sinus infection is very high. The main problem starts occurring after the sinus infection is not treated properly or is not considered a medical emergency. Due to swelling of sinus cavities, there is a stagnant pool of mucus created in the cavity area that acts as the perfect substratum for germs. When the sinus openings are blocked by dry mucus, the pressure in the area becomes high and there is a decreased blood flow. Due to lack of blood flow in the cavity area, the body is unable to fight infection and hence, it leads to worsening of the infection. Left untreated for a long time, it can be a cause of medical emergency leading to brain infections. If that occurs, it can be certainly called one of the serious complications of sinusitis. Sinus infection is harmful and can be deadly, if it is not treated properly and before time. Hence, people who are suspicious of their frequently occurring common cold must not hesitate to visit a doctor at the earliest.