Regulators have given the green light to the first alopecia treatment proven to regrow hair.

Trials have shown that taking the daily pill can almost entirely reverse the condition that causes hair to fall out in clumps.

It works by interrupting faulty signals that make the immune system attack hair follicles.

NHS spending chiefs will now review baricitinib and decide whether the health service will fund the treatment for alopecia.

Charities and doctors celebrated the news, and called for the NHS to pay for patients with the most severe form of alopecia to receive baricitinib as soon as possible.

'This is a really important step in the right direction for a group of patients who up until now had no effective treatment options,' says Sue Schilling, chief executive of the charity Alopecia UK.

Trials have shown that taking a daily pill can almost entirely reverse alopecia which causes hair to fall out in clumps.

About 100,000 Britons have a condition called alopecia areata, where cells in the immune system attack hair follicles, for reasons not understood.

Some people also lose eyebrows, eyelashes and hair elsewhere on the body.

Studies show that, for a third of patients, baricitinib sparks hair regrowth within three months and it continues to grow back.

Patients who respond to the treatment see 80 per cent of their hair return.