The American Academy of Allergy, Asthma and Immunology (AAAAI) has warned that if stuffy nose, headache and other symptoms of cold last for more than two weeks, it may be sinusitis.
"Early on, the symptoms of colds and sinusitis are similar. But if symptoms are worsening after 3-5 days, or if they are present for more than 10 days, then sinusitis is the likely culprit," said Dr. Anju Peters, Chair of the AAAAI Rhinosinusitis Committee.
Sinusitis occurs results from a blockage of drains in the sinus cavities - hollow areas behind the forehead and cheeks - due to inflammation caused by a cold or allergies. The blockage does not let mucous drain normally, and thus lead to infection.
Doctors usually treat the infection with antibiotics, and patients may use decongestants to relieve stuffiness.
However, its better to see an allergist or immunologist because he/she can help treat underlying allergies that contribute to sinusitis.