Can you really be allergic to exercise? Yes – and it sounds awful.

Does your skin get really itchy when you run, bike, or lift weights? If it does, you could suffer from a physical allergy that causes you to itch when you exercise. Greatest allergy ever? Sure, maybe – unless you've got the version that makes it miserable to even climb stairs.

Top photo by Ed Yourdon via flickr

As Roberta Kwok explains in a recent post at Last Word on Nothing, the condition is called "cholinergic urticaria." According to Kwok – who thinks she may suffer from the allergy, herself – the symptoms, while rare, can be downright excruciating:

A quick Google search brought up complaints from dozens of fellow sufferers, who described the sensation as “an INSANE itch,” “pure hell,” and enough to make them want to “scratch until I bleed,” “take a knife to my legs,” or — my favourite — “blast my face off.”

Strangely, cholinergic urticaria patients can exhibit a "spectrum of allergic symptoms ranging from an erythematous, irritating skin eruption to a life-threatening anaphylactic reaction." What's more, not all people are as sensitive to the allergy as others. Kwok, for example, says she can do yoga without itching, but not running. She also says that treatment for the allergy can be difficult to nail down:

Some people have found relief by taking antihistamines before they run. One 25-year-old patient, however, had a case so severe that he began to itch even when climbing a flight of stairs or carrying groceries. Antihistamines didn’t help him, but antibodies against immunoglobulin E, a protein involved in allergic reactions, did.

Read more about exercise-induced itchiness, and other theories for its symptoms, over at Last Word on Nothing.