Credit: Denise Goolsby/The Desert Sun

Angry bees swarmed two people in Indio, Calif. this morning, sending them to the hospital with almost 200 stings in all.

Dr. Wesley Burks, who chairs the University of North Carolina's pediatrics department and has a 30-year career that involves working with skin allergies, said an attack like that is rare. If fact, he's never seen one firsthand.

"Generally, you see somebody stung once or maybe five to ten times, but not 80 or 100," Burks said. "I've talked to people that have seen them…but it's less than a handful."

A gardener in Indio, whose name was not released, was trimming a palm tree just before 7 a.m. local time, when he apparently irritated the bees and prompted them to swarm around him, said Matt Kotz, a Riverside County firefighter, in an interview with ABCNews.com. The homeowner, an elderly woman, came out to help, but the bees attacked her as well.

When Kotz and the other firefighters arrived, the bees were still attacking the victims on the ground, Kotz said. He said he watched as another crew sprayed the bees with water to fight them off.

The bees stung the woman more than 100 times, and they stung the homeowner more than 80 times, according to the Riverside County Fire Department.

Burks said a large number of stings like this can often lead to anaphylactic shock - even if the patient is not allergic to bee stings.

Each sting releases proteins into the victim's body, causing swelling and eventually resulting in a histamine reaction - as if the body were reacting to an allergy. Sometimes, that swelling can even affect the victim's ability to breath, Burks said.

Burks said bee stings generally affect people the same way, regardless of age, but conditions like hypertension and diabetes can make it harder to respond and recover.

No firefighters were injured because they wore gloves and bee hoods in addition to their helmets, Kotz said.

Although firefighters are trained to kill bees with the same foam they use to put out fire, Kotz said the bees were left alone after the attack.

"We didn't want to kill the swarm," Kotz said. "Obviously bees do good to the environment…and they weren't actively stinging."

He said the bees were on private property and posed no risk once the attack ended. The fire department left it up to the homeowner to decide whether to remove them.