Winter is an allergy season for people allergic to indoor allergens.
For Aaron Shiffrin and Ghlib Alsharif, their allergies are more than a sniffle.
Both men say their allergies can be crippling at times.
"I've tried to work through it and not make it a factor, but it's debilitating,” said Shiffrin. “If you've ever been sick before, you know what it's like when you have the flu. It's very similar."
Now a new study is showing that allergies affect more than the respiratory system.
It could actually be affecting the brain.
Allergist Dr. Talal Nsouli led the study which looked at 98 patients suffering from seasonal and environmental allergies.
Of those patients, 82 percent of them say they experienced extreme fatigue and lethargy.
After 8 weeks of allergy treatment, 72 percent felt more awake and had increased energy levels.
Nsouli says this is more evidence that when allergens enter the body, chemicals like histamines can actually slow down brain function.
So people will not only feel fatigue, they can feel irritable, depressed, and even have symptoms similar to attention deficit disorder.
Other studies have even linked allergies to chronic fatigue syndrome.
Shiffrin says he'd been getting allergy shots for years.
It's helped him not only breathe easier, but he feels like he's finally able to enjoy life.