Feeling itchy? Scientists are working to unravel the mysteries behind chronic itch

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Candice Coghlan spent much of her time in high school missing class after scratching large areas of her legs, back and scalp, without knowing the itching was due to a silent disease. 

When Coghlan returned home to Waterloo during her second year of university, she'd lost weight on top of the skin issues. Hours after blood was drawn, the lab called telling her to go to the emergency department immediately. 

Coghlan, now 38, was told she was in end-stage kidney failure. 

Looking back, the itching she thought was from ordinary psoriasis was actually a clue. 

"With my failed kidneys, it was actually the toxins trying to escape through my skin because my kidneys could no longer process the toxins, causing extreme itchiness," Coghlan said.

She was on dialysis for more than a year. In September 2009, her mother donated a kidney to her. 

"It was by day two, I would say, of having my kidney transplant that I realized I was no longer itchy," she recalled. 

Chronic itching can be a sign of a deep, underlying problem like liver or kidney disease, as it was for Coghlan.

But even when the cause is more benign, which is more common, the itching itself can have a major impact on someone's quality of life, say dermatologists, and it's not well understood.

Why is itching contagious? Why do we keep scratching ourselves, beyond when it helps? Scientists are still unravelling the head-scratcher of itching — from how hard we scratch the skin to neurons in the brain that could explain what's going on.

Dr. Rachel Asiniwasis, a dermatologist based in Regina, said atopic dermatitis — more commonly called eczema — tops the list of what she treats in her office.

The itching can be as harmful to patients as chronic pain on a mental health level, she said. 

"I feel like it's a condition that's often misunderstood or dismissed as just a skin problem," Asiniwasis said.