Allergy season is in full swing for many, but as many begin to report itchy and watery eyes, congestion and sneezing, what exactly is causing them?
According to Dr. Rachna Shah with the Asthma and Allergy Center of Chicago, levels of mold and weed are currently the highest in the metro area as of Thursday.
While that is typical for the fall allergy season, this year is particularly high, Shah said.
"Mold typically is high this time of year, but has been very high this year due to the rains and the humidity along with higher temperatures," Shah told NBC Chicago in an emailed statement.
In addition to elevated mold and weed levels, the ragweed and other weeds are often heightened from mid-August through the end of September, experts said. Those levels are indeed increased in the Chicago area, but the levels remain average for now, Shah said.
According to Loyola Medicine's daily allergy count, the levels as of Thursday were reported to be:
Molds: VERY HIGH
The count is collected daily on the roof of Gottlieb Memorial Hospital.
What exactly are allergies and why do people react differently?
If you have an allergy, your immune system overreacts to a substance you inhaled, touched or ate, according to the American Academy of Allergy, Asthma and Immunology.
"Allergies are inherited. People inherit the ability to be allergic, but they don't exactly inherit what they're allergic to," said Dr. Richard Wasserman, medical director of Pediatric Allergy and Immunology at Medical City Children's Hospital in Dallas, Texas. "So, people who have one parent with allergies have about a 50% likelihood of developing allergies. If both parents have an allergic disease, it's about 80%."
Seasonal allergic rhinitis, commonly known as hay fever, is usually triggered by outdoor allergens such as pollen and mold spores.
"Rose fever, hay fever are, kind of, colloquial names for allergy. Hay fever is probably mostly caused by mold," said Wasserman. "Mold is another thing that people get allergic to. Mold likes to grow in moist environments like haystacks or barns, so that's the association there."
So when might you see some relief?
"We will likely see elevated mold levels until the first frost," Shah said.