Nine-year-old Priscilla Pomerantz can't play in the snow, eat ice cream or walk her dog during the winter. She can't get cold at all, because she suffers from an allergy called cold urticaria. For Priscilla, air temperatures below 70 degrees -- or even eating chilly foods -- trigger an allergic reaction of hives, swelling and difficulty breathing. Left untreated, the cold could literally kill her.
"I do worry about it. It's something that we worry about everyday," Craig Pomerantz, her father, told TODAY.
Priscilla was diagnosed two years ago, after she broke out in hives while swimming. At first her mother thought she must be allergic to sunscreen. But after weeks of testing, doctors determined the problem was cold -- using an ice cube as a tester.
"I didn't cry. But on the inside, I felt horrible," Priscilla said about learning her diagnosis.
Cold urticaria affects 15 to 25 percent of Americans at some point in their lifetime, according to Dr. Nancy Snyderman; children are more likely to have it than adults, but a severe allergic reaction like Priscilla's is rare. No one is sure what causes it, according to the Mayo Clinic. Priscilla takes antihistamines twice a day and carries an EpiPen everywhere. Doctors say she may grow out of the allergy -- or may not, they don't know.
For now, her family just has to wait and see, and be vigilant to keep their daughter warm. For example, her father drives her to school every morning, warming up his car first, because the school bus is too drafty. At school, she sits next to a space heater. Her bath water has to be as hot as she can stand it, and her parents are waiting with heated towels when she's done.
Sometimes, people think the parents of children with cold allergies are just being overprotective or a little kooky, Snyderman said on TODAY, but the illness is quite real. "This is a well recognized medical problem," Dr. Snyderman said, similar to nut or shellfish allergies. "This is just one that's not as well known."
Related: Unusual allergies triggered by iPods, celery, sun
Priscilla lives with her family in upstate New York, where winter temperatures commonly dip into the teens and below. Why not move to a warmer climate, like Arizona or Florida, TODAY's Matt Lauer asked her parents.
"It's actually almost worse, because everything in Florida is air conditioned," her father replied. Indoor air conditioning triggers Priscilla's allergy, too -- her mother, Colleen Lynch, brings blankets to keep her daughter warm when she wants to go out to the movies.
(Lauer told the audience that Priscilla wasn't put in any danger by appearing on the TODAY show: She's fine outside as long as she's bundled up, and producers made a note to turn the thermostat in the studio up to 72 degrees for her visit.)
Priscilla has had to give up a lot of things she likes, such as ice cream and sledding. But she tries to look on the bright side. "In the wintertime some of it's good," she told TODAY, "because I don't have to walk the dog, and I don't have to shovel snow."