ABC News' Linzie Janis reports:
Carolyn Taylor of South Salem, N.Y., was rock climbing with her husband and some friends nearly 10 years ago when she was stung four times by bees.
She'd been stung by a wasp a few years prior - as well as once as a young adult - and despite experiencing what she'd called a "funny feeling," was fine and did not go to the doctor. This time, though, she noticed a difference immediately.
"My hands were really itchy. I felt like I could feel my face growing," she said. "I called my husband to come over and have a look at me, and I could tell by the look on his face that something was really wrong."
With August being prime time for bee stings, immunologists are warning people to be alert.
"Five percent of the population has insect sting allergies," said Dr. Beth Corn, an assistant professor of medicine at the Mount Sinai School of Medicine. "Allergies in general are on the rise…. There are [no warning signs] and that's what makes this so tricky…. One would never know that they're going to have a bad reaction if they've never been stung before."
And 3 percent of all Americans, like Taylor, could have a severe, life-threatening reaction and not know it or be prepared for it because an allergic reaction can surface at any point in your life.
"Anyone that's had a reaction should see a [board-certified allergist] and discuss it," Corn said.
By the time Taylor arrived at the hospital, she was in anaphylactic shock. She was covered in hives and her blood pressure was extremely low.
"I just tried to stay really calm because I knew it was, I knew what was happening to me," she said. "It was scary."
Experts advise avoiding sweet-smelling perfumes when heading outside, keep a lid on outdoor garage cans, and don't walk barefoot outside. Yellow jackets build nests in the ground and hornets nests are also low to the ground. They also say that if approached by bees, walk calmly and slowly away because bees sting when threatened.
Doctors say that if you're stung and have difficulty breathing, swelling of the throat or a weak pulse, go straight to the emergency room. They also suggest that those with allergies carry epi pens.
Taylor later found out that the "funny feeling" she'd had after being stung by a wasp years earlier had been a red flag, a precursor to an anaphylactic reaction. For three months after being stung and seeing her doctor, she continued to suffer chronic hives and was prescribed prednizone and antihistamines, to no avail.
"For that first three months, I barely went outside…. I'd go to the farmers market and there'd be bees all over," she said. "You look at them and think, This little, tiny thing is going to kill me."
She finally sought a venom immunotherapy treatment, which worked.
"It's great," Taylor told ABC News. "We can go hiking. We can go backpacking. We can go out in the woods…. It's given me back my life, being able to go outside and enjoy nature and do things without fear."