Allergies, hay fever and other allergic reactions can be triggers for acute or chronic sinus infections (sinusitis). When allergies flare up, it often triggers swelling in the sinus and nasal mucus linings. When these symptoms persist, the sinus passages are liable to close up, causing bacteria to be trapped in the upper respiratory tract. With the buildup of bacteria, often comes infection.
The Biology of Sinusitis
The sinuses are air-filled cavities in various places on the head. They are located:
- Sphenoid Sinuses – Just behind the nose, and directly in front of the brain
- Ethmoid – Either side of nose, up by the bridge
- Frontal Sinuses – Behind both the eyebrows and the rest of the forehead
- Maxillary Sinuses – Within the structure of the cheekbones
When sinus passages become blocked, the cavities often fill with bacteria, causing swelling and facial pain, amongst other symptoms.
Most instances of acute sinusitis are a mild development of the symptoms caused by allergies, and will disappear a couple of weeks after the symptoms are first experienced. Other infections that persist are considered to be chronic sinus infections and may take antibiotics to clear up.
When the infected sinuses are close to the brain, chronic sinusitis can cause complications where the infection spreads to the brain.
Sinuses in their normal, healthy state are lined with a thin layer of mucus that is designed to trap dust and germs. Then tiny hair-like projections within the sinuses sweep all the mucus and other particles trapped in there towards openings that lead to the back of the throat. From here, it slides into the stomach, which is the final stage in this normal bodily function.
When a sinus infection is present, it prevents the normal flow of mucus that carries it to the back of the throat. The hair-like projections become blocked as a result of swelling, which keeps the mucus trapped in the sinuses.