A sinus infection, also known as sinusitis, is an inflammation of the sinuses caused by a buildup of fluid and germs. Symptoms include facial pain and pressure, a stuffy or runny nose, and thick mucus.

Symptoms
• Runny or stuffy nose • Facial pain or pressure • Headache • Thick mucus • Loss of smell • Fever • Sore throat • Cough • Bad breath

Causes
• Colds, the flu, or other viral infections
• Bacterial infections, such as Streptococcus pneumoniae
• Seasonal allergies
• Structural problems in the sinuses
• A weakened immune system

Types
• Acute sinusitis: Symptoms last less than 4 weeks
• Sub-acute sinusitis: Symptoms last 4 to 8 weeks
• Chronic sinusitis: Symptoms last 8 weeks or longer
• Recurrent sinusitis: 3 or more episodes of acute sinusitis in a year

When to seek medical advice
• You have a fever
• You have swelling or redness around your eyes
• You have a bad headache
• You have confusion
• You have double vision or other vision changes
• You have a stiff neck
• You've had symptoms for weeks