Sinusitis is an infection or inflammation in the mucous membranes that line the sinus cavities . Most of the time, sinusitis is caused by a virus. But it can also be caused by bacteria. Most people who get sinusitis have a cold first. Sinusitis can cause pain and pressure in your head and face.

There are two types of sinusitis:

• Acute (short-term). Acute sinusitis is usually caused by a virus. It can last for 2 to 4 weeks. Symptoms often start to clear up on their own in 10 to 14 days.
• Chronic (long-term). Chronic sinusitis is usually caused by bacteria. Sometimes it is caused by a fungus. It can last for 12 weeks or longer and can be hard to treat.

Your treatment will depend on the cause of your sinusitis. Most of the time, treatment includes medicines and taking care of yourself at home. Medicines that are used most often include:

• Decongestants, such as Sudafed, that are taken as pills or liquids. These can reduce swelling and improve sinus drainage.
• Over-the-counter pain medicine, such acetaminophen (for example, Tylenol) or ibuprofen (for example, Advil).
• Antibiotics, which kill bacteria. Antibiotics will only work if your sinusitis is caused by bacteria. Most of the time, sinusitis is caused by a virus.

You may have a bacterial infection in your sinuses if:

• You have pain in your cheeks or upper back teeth and a high fever that doesn't go away.
• You have a lot of bright yellow or green drainage from your nose for more than 10 days.
• Decongestants do not relieve your pain.
• Your symptoms get worse instead of better after your cold is gone.

Antibiotics work in most cases of acute sinusitis that are caused by bacteria. Most people start feeling better 3 to 4 days after they start taking the medicine.

Antibiotics won't work for infections caused by a virus. Over-the-counter medicines and home treatment can help you feel better.

Taking antibiotics you don't need won't help you feel better, cure your infection, or keep others from catching your infection. And if you take antibiotics too often, they may not work when you really do need them.

Common but mild side effects of antibiotics include:

• Upset stomach.
• Diarrhea.
• Belly pain.
• Vaginal yeast infections .

If you do take antibiotics, take them as directed. Keep taking them even after you start to feel better. The infection may not go away if you don't take all of the medicine your doctor prescribes.

Whether sinusitis is caused by bacteria or by a virus, most people get better even if they don't take antibiotics. ^{footnote 1} Home treatment for sinusitis can help relieve your symptoms. Here are some things you can do:

• Drink plenty of fluids to thin your mucus.
• Apply moist heat (using a hot, damp towel or gel pack) to your face for 5 to 10 minutes. Do this at least 3 times a day.
• Breathe warm, moist air from a steamy shower, a hot bath, or a sink filled with hot water.
• Use saltwater nasal washes to help keep your nasal passages open and to wash out mucus and bacteria. You can buy saline nose drops or sprays at a pharmacy or make your own saline solution at home. If you make saline at home, use distilled water or water that has been boiled and then cooled. You may also find it helpful to gargle with warm salt water.
• Ask your doctor if you can take over-the-counter medicines such as pain relievers and decongestants to help you feel better. Be safe with medicines. Read and follow all instructions on the label.
• If you need to blow your nose, do it gently. Blowing your nose too hard may force thick mucus back into your sinuses. Keep both nostrils open when you blow your nose.

You doctor may recommend antibiotics if:

• You have symptoms of a bacterial infection and you have not gotten better after 10 days, even with home treatment.
• Your symptoms are severe, or you have other problems, such as pus forming in your sinus cavities.
• You have had sinusitis for 12 weeks or longer (chronic sinusitis).