The frontal sinuses are located above the eyes; when they are inflamed, the result is swelling above the eyebrows, according to PDRhealth; the medical term for this condition is sinusitis. Sinuses are air-filled spaces within the bones of the face, around the nose.
There are four main pairs of sinuses: frontal (above eyes); maxillary (within cheekbones); ethmoid (behind the nose bridge); and sphenoid (behind eyes). The inflammation of sinuses causes swelling and the trapping of air and mucous, which results in pain and a blocked up feeling, according to Bupa.
Acute sinusitis lasts up to 4 weeks, and is caused by infection of the mucous membranes in such instances, as when a person has a cold. If the mucous becomes infected with bacteria, then the result is bacterial sinusitis.
Chronic sinusitis lasts longer than 12 weeks and is caused by irritants and allergens. Examples of irritants and allergens include pollen, dust, smoke, pollution and household detergents. Symptoms of sinusitis are pain on the top of the head, within the ears, the top of the jaw and teeth or cheeks, and between the eyes. Other symptoms are a stuffy nose, loss or reduction in the sense of smell, green or yellow mucus which drains to back of the throat or a fever. Less frequent symptoms are lethargy, coughing or a sore throat and bad breath.