Connor Frankenfeld first developed the strange rash when he was 3 years old. Connor's parents and doctors were mystified, but the rash only got worse. It took a year for a specialist to finally diagnose Connor's condition: The little boy was allergic to the cold.

Cold urticaria is a very rare condition affecting about one in 100,000 people, according to ABC News. In fact, Connor's doctor, William Lanting with Colorado's Asthma and Allergy Center of the Rockies, said he's only seen four or five cases in three decades of allergy specializing, according to ABC 7.

People with cold urticaria can develop redness, itching, swelling and hives on the skin after coming in contact with cold temperatures, according to the Mayo Clinic. Normal activities become potentially life-threatening. For example, swimming in cold water is the most common cause of a severe, whole-body reaction leading to fainting, shock and even death.

Grant Schlager, a 12 year-old from Minnesota, takes a twice-daily antihistamine and keeps an emergency EpiPen handy in case his cold urticaria flares up suddenly. Grant was diagnosed with the condition at the Mayo Clinic in Rochester, Minn., according to USA Today, but the strange diagnosis was initially hard to swallow.

"I had never heard of it and I was skeptical," Grant's mother, Amy Schlager, said. "How can anybody be allergic to cold?"

Researcher Joshua Milner may know at least part of the reason. In a study published online in January by the New England Journal of Medicine, Milner and his colleagues found a genetic mutation in 27 people from three families who all had cold urticaria mixed with other immune system abnormalities and disorders.

"In trying to understand the link between this group of conditions -- autoimmunity, chronic infections and cold urticaria -- we not only identified a disease-causing mutation but uncovered a unique and fascinating genetic mechanism at the crux of allergy, immune defense and self-tolerance," Milner told Health Day News.

Connor's 8-year-old sister Taylor has now also been diagnosed with the disorder, and hers is more serious than Connor’s: Her school's air conditioning almost pushed her into anaphylactic shock.

Now, the Frankenfeld's are careful. The kids never leave the house without gloves, scarves and jackets, and when the temperatures dip into single digits they aren't allowed out of the house at all, according to ABC 7.

Melissa Franfeld has set up a Facebook page, where parents with children suffering from cold urticaria can share tips and find support.

There is no cure for cold urticaria, but treatment and precautions can help, according to the Mayo Clinic. The clinic suggests avoiding cold temperatures and taking certain antihistamines before exposure.

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