Connor and Taylor Frankenfeld -- allergic to the cold. (Image Credit: Courtesy of Melissa Frankenfeld)

While many people get sick in cold weather, a small number develop an allergic reaction to the cold - literally. Much as with food and pollen allergies, reactions can include rashes, hives that can extend almost to an inch, closing of the throat and general itchiness.

Mike and Melissa Frankenfeld of Sterling, Colo., are all too familiar with this rare condition, called cold urticaria.

Their battle started two years ago when they noticed a painful rash on their son, Connor, who was 3 years old at the time.

"It was really weird," Melissa Frankenfeld told ABCNews.com. "We saw this rash in the diaper area, and I thought 'diaper rash,' and I treated it with home remedies and it got worse. I tried changing detergents and soaps, and I took him to the doctor, because it wasn't getting any better. They said it was diaper rash, and to let it air out."

The rash continued to worsen and even began to swell as the Frankenfelds made the rounds of several more doctors, none of whom could hit on the right treatment. The only thing that seemed to soothe Connor was warm baths.

Finally, after a year of going from doctor to doctor, the Frankenfelds found Dr. Bill Lanting, at the Asthma and Allergy Center of the Rockies. Lanting, who'd also founded the website America's Allergist, performed a simple test in which he pressed an ice cube against Connor's arm for four minutes, and watched as hives formed. That's when he knew Connor had cold urticaria.

"You have these mast cells, or allergy cells that are found mainly in the skin, and are set off by allergens like food, medications and stinging insects," Lanting told ABCNews.com. "Exposure to cold or literally holding a coke can or ice cube can set off the mast cell, so if you're exposed to cold at a certain temperature, you can get hives. Hives you can deal with using Benadryl, but if it's severe enough it can cause throat swelling and breathing problems."

Lanting said cold urticaria was rare, affecting approximately one in 100,000 people.

In the throes of trying to get Connor diagnosed and treated, the Frankenfelds learned that their daughter, Taylor, 8 years old, also had cold urticaria, and her condition was even more serious than Connor's. She almost went into anaphylactic shock after she was exposed to air-conditioning at her school.

"I just feel my throat start to feel funny and it was feeling like it was getting bigger," Taylor told ABC 7 in Denver. "I was really scared. I thought I was going to die."

"There's nothing you can do," Melissa Frankenfeld said. "I stay at home, and the school has me on speed dial. Every day I go to school for recess."

Lanting said cold urticaria could be controlled by taking a daily chronic antihistamine, but so far there was no definitive cure.

Dr. Clifford Bassett, an assistant clinical professor of medicine at New York University, and founder of allergyepidemic.com, said that in general, most people with cold urticaria had manageable symptoms that were not life-threatening.

Bassett said he'd treated a patient just today who has lived with the rare allergy for 20 years - his symptoms appear only in response to cold water, not cold temperatures.

He said cold urticaria could have a genetic cause, but it could also be acquired (usually between the ages of 18 and 25) or result from another medical condition.

Melissa Frankenfeld, who said she has received an outpouring of support from other parents dealing with this rare allergy, believes more research is needed.

"When Connor was first diagnosed, we were told he's either going to grow out of it, it will stay the same or it will get worse, but there is not enough information out there to know for sure," she said.

Moving to a warmer climate was not a solution, said Frankenfeld, as cold countertops, cold bathtubs, ice cream, popsicles, air-conditioning and cold drinks can all trigger a reaction.

"Even if they walk on wooden floors, their feet will break out," Frankenfeld said. "Even running and getting sweaty against the air can cause a reaction."

Mike and Melissa Frankenfeld try to their best to maintain a normal life for their children.

"They have to be kids," Melissa Frankenfeld said. "They have to have a life, and they have to enjoy all the things that kids enjoy in life. They need to have the ice cream and the popsicles, but we do take the appropriate precautions. We let them play in the snow, but we bundle them up and … and we carry Benadryl because that's the only thing you can do when a reaction does start."