Sinuses are hollow spaces inside the bones of the skull which are interconnected and lined with a thin layer of tissue. Healthy sinuses are not filled with anything except air, which circulates through the network of sinuses, but mucus can build up in the sinuses and cause a feeling of congestion and pressure. Sinus pain and pressure can be caused by a variety of different conditions, such as allergies, sinus infections, respiratory infections and sinus blockages.
Sinus problems can sometimes cause a headache that may be confused for a tension headache or a migraine. Sinus headaches often feel like pressure behind the eyes, in the forehead, or in other parts of the face. They tend to be worse in the morning and when the weather changes abruptly. Sinus headaches can be triggered by an upper respiratory infection such as the common cold. Unlike migraine headaches, there usually isn’t light and sound sensitivity associated with sinus headaches.
Sinusitis is inflammation of the tissue in the sinuses. Acute sinusitis is usually caused by an infection with a virus or bacterium. This inflammation causes mucus production, sinus pressure and congestion. Some sinus infections can cause other symptoms, such as fever, fatigue and sore throat due to dripping of mucus from the nasal cavity to the back of the throat. Abnormal growths called nasal polyps can be triggered by inflammation of the nasal cavity and sinuses over time.
Allergies can also lead to sinus inflammation. Allergies are caused by an improper immune response to substances called allergens, which are commonly things like pollen, dust, mold and pet dander. Pollen especially is a major cause of seasonal allergy symptoms. Allergies also cause inflammation, leading to the same problems as sinusitis, but sneezing and itching are additional common symptoms.
Some people seem to be more susceptible to sinus problems; the shape of their sinuses may play a role because narrower sinuses can be blocked off more easily by inflammation. Blocking the exits of the sinuses can cause a buildup of mucus and inability of the sinuses to drain, which may lead to secondary infections over time. For example, if a person has inflammation in their sinuses due to a cold, blockage of the sinuses can provide a perfect place for bacteria to grow and cause a more severe infection.