By Stephanie Stahl

PHILADELPHIA (CBS) — Doctors say the constant need to scratch can be as debilitating as chronic pain, but now scientists are working on a potential new treatment.

Certain medical conditions, like eczema and psoriasis, can cause itching, but for some people, there’s no known cause.

Scientists at the world’s first Center for the Study of Itch at Washington University School of Medicine say they’re getting closer to finding answers for patients who are desperate.

Don Hodges has battled enemies at war and a bout with cancer, then came a chronic itch all over his body.

“I went through so many dermatologists,” said Hodges. “They couldn’t do anything.”

Creams, ointments and medication didn’t help. Hodges is among 15 percent of people who suffer from unexplained chronic itch.

“Study after study has shown that it’s worse than chronic pain or comparable. My patients tell me it’s often worse,” said Dr. Brian Kim of the Washington University School of Medicine.

After discovering an itch molecule, scientists expanded their work, from testing treatments on itchy lab mice to finding relief for desperate patients.

“A lot of people didn’t believe that not only that it wasn’t a real problem, that it was a problem we could solve at the scientific level,” said Kim.

Doctors finally found a way to help Hodges. After several failed treatments, an arthritis drug is giving him relief.

“Within a week, probably from the day I took it, and it went away and hasn’t come back,” said Hodges.

Scientists now hope to expand their research.

“It doesn’t have to stop here. That’s just one drug, one pathway, but we think there’s a lot more,” said Kim.

Doctors say constant scratching can cause skin problems and infections, and can also lead to depression.

Currently, there’s no FDA-approved treatment for chronic itch.