THURSDAY, Sept. 22, 2016 (HealthDay News) -- For people who suffer from a condition that causes disfiguring hair loss, a drug used for rheumatoid arthritis might regrow their hair, a new, small study suggests.

Alopecia areata is an autoimmune disease that causes patchy or complete hair loss, including on the head, body, eyebrows and eyelashes.

Researchers found that more than 50 percent of 66 patients treated with the drug Xeljanz (tofacitinib citrate) saw hair regrowth in three months.

"There is hope now that we will have more to tell patients than get counseling and a wig," said lead researcher Dr. Brett King, an assistant professor of dermatology at the Yale School of Medicine, in New Haven, Conn.

Xeljanz appears to work by stopping the immune system's attack on hair follicles, King said. In addition, the researchers have identified genes that might predict a patient's response to treatment, he said.

King said it is doubtful that Xeljanz will work for the most common types of hair loss (such as male pattern baldness), which are not the result of an autoimmune disease.

Whether the hair regrowth will last or how long someone would have to take the medication isn't known, King noted.

"It may be that if we can treat people for long enough the condition might go into remission, but we don't know the answer to that," he said.

For the study, King and colleagues treated the patients with 5 milligrams of Xeljanz twice a day for three months.

Over that period, more than 50 percent of the patients saw some hair regrowth and one-third recovered more than half of the lost hair on their head, King said.

Side effects were mild, he added.

King hopes that a big drug company will look at these results and sponsor larger trials to seek FDA approval for using Xeljanz as a standard treatment for the 4 million to 11 million Americans with alopecia areata.

Treatment with Xeljanz is expensive, costing as much as $40,000 a year. Because the drug is not approved for the treatment of alopecia areata, it may not be covered by insurance for that use, King said. Doctors, however, may be able to convince insurers to cover the cost, he added.