Understanding what illness you have is important in figuring out how to treat it, and how to get rid of it.

Garyl Hester of new York City thought he had a sinus infection when he went to the doctor – but he had it all wrong.

“I couldn’t get rid of it, I couldn’t shake it,” said Hester, 48. “So (my doctor) tested me and found out I was allergic to dust mites, which I never knew before.”

Hester said he now has an air purifier in his house and he bought hypoallergenic sheets – and his headache is gone.

New York-based allergist Dr. Jonathan Field said most patients get confused and often do not know what kind of medical condition they are dealing with.

“If they have a fever, if the headache tends to be more extreme or if they lost their sense of smell, then it sounds to me like a sinus infection,” Field said.

If you are prone to sinus infections, try an irrigation rinse to prevent them or get tested for allergies.

Field said colds and sinus infections are often triggered by indoor allergies, such as dust, mold and pet dander.

“Colds tend to be mild, and you have typical symptoms like a running nose, itchy eyes – a little bit of a sore throat and mild muscle aches, but generally you feel well,” Field said.

Cold symptoms should not last longer than a week, he added. Taking zinc at the onset of a cold can decrease the duration of the illness and severity of symptoms.  

However, the flu is much worse – symptoms are more pronounced in terms of muscle aches and fatigue, and you will definitely have a fever.

The onset of the flu is very sudden, Field added.

Prescribed medication is the only cure for influenza, which can be deadly. up to 36,000 Americans die each year from influenza, so if you think you may have it, see a doctor immediately. A flu shot is the best prevention.