Sinuses are hollow air spaces lined by mucous membranes located within the skull or bones of the head. All the sinuses open to the nasal cavity (large air-filled space above and behind the nose) for free exchange of air and mucus. They are also known as paranasal sinuses, and they have four subgroups depending upon the types of bones in which they are present. These subgroups are: maxillary, frontal, ethmoid, and sphenoid. Any type of infections, inflammations, and allergic reactions block the sinuses and result in congestion of the nasal passages. In such cases, the person may experience pain and pressure in the head and around the face. This may also lead to attacks in of any of the four paranasal sinuses. Sinusitis or sinus infection is caused due to inflammation of the paranasal sinuses due allergies and other infections such as bacteria, viruses, fungi, etc. Other causes of sinusitis include poor air quality, temperature, humidity, weak immune system, dehydration, hormones, and stress. Sinusitis is classified into four types based on the type of sinus that has been affected.

• Maxillary sinusitis: Patients may experience pain in the cheek area.
• Frontal sinusitis: Patients may experience pain over the eyes and in the eyebrow region.
• Ethmoid sinusitis: Patients may experience pain between the eyes and behind the nose-bridge.
• Sphenoid sinusitis: Patients may experience pain in the upper areas of the nose.

Since the symptoms are uncertain and people have pain in multiple locations, it is difficult to identify which sinus has been inflamed. Based on the duration of the sinusitis inflammation, it has been classified into acute, lasting for less than 1 month, or chronic, in which a person is affected for a longer period of more than 3 months. Acute sinusitis is mostly due to common cold caused by viral infection, whereas chronic sinusitis is caused by a number of factors such as allergy and pollution. A combination of acute and chronic sinusitis signifies recurrent sinusitis. The symptoms include persistent cold with cough, stuffy nose, sore throat, bad breath, nasal congestion, decreased sense of smell, fever, fatigue, weakness, post nasal drainage, headache and facial pain, and pressure. Other symptoms also include earache, voice hoarseness, and swollen eyelids. The treatment for sinusitis includes a prescription of antibiotics, pain relievers, decongestants, and nasal irrigation (washing of nasal cavity to flush excess mucus). Certain herbal remedies may also be used to alleviate the symptoms. If acute sinusitis is not treated at the right time, then there may be a risk of chronic sinusitis progression. Therefore, it is always recommended to consult a qualified health specialist in case of any sinus related problem. Disclaimer: This Buzzle article is for informative purposes only, and should not be used as a replacement for expert medical advice.