what causes sinus congestion
Causes. Sinus headaches can be caused by sinus congestion and inflammation, called sinusitis. Sinusitis, in turn, is caused by either a respiratory infection, such as a cold or flu, or allergies, like hay fever.Healthy sinuses allow mucus to drain and air to circulate throughout the nasal passages.auses. Sinus headaches can be caused by sinus congestion and inflammation, called sinusitis. Sinusitis, in turn, is caused by either a respiratory infection, such as a cold or flu, or allergies, like hay fever.