Two main types of sinusitis include:

• Acute sinusitis
• Chronic sinusitis

Acute Sinusitis
A person who has had symptoms of sinusitis for less than 3 weeks has acute sinusitis. Viruses are the most common cause for acute sinusitis, but some cases are caused by bacteria.

Common bacterial causes of sinusitis:

• Branhamella catarrhalis
• Haemophilus influenzae
• Staphylococcus aureus
• Streptococcus pneumoniae
• Streptococcus pyogenes

Chronic Sinusitis
A person who has had symptoms of sinusitis for more than 3 weeks has chronic sinusitis. It is most common in those who have persistent nasal congestion caused by allergies. Mold is a common cause of nasal allergies and chronic sinusitis.