Finance Minister Jim Flaherty has gone public in a deeply personal interview with the Globe and Mail to explain some recent dramatic changes to his looks.

Flaherty has lately found himself fielding questions from colleagues and others about his health and the noticeable change to his appearance.

His face has grown bloated and puffy and he’s gained a significant amount of weight.

To quell concerns, Flaherty gave an interview to the Globe and Mail, explaining that he has a rare skin disease (called bullous pemphigoid) that requires strong steroid treatment.

Flaherty, 63, said while he is reluctant to speak about his health, he wants to assure Canadians that neither the condition nor the medication affects his ability to do his job as federal treasurer.

Pemphigoid is a rare blistering skin disorder that can produce lesions on parts of the body.

The MP for Whitby-Oshawa spoke to the Globe in his Parliament Hill office on Wednesday and the report said he appeared uncomfortable divulging details on such a private matter.

“Most people are quite cautious about what they say, but a few people have said to me, ‘Do you have cancer? … What’s going on? Are you going to die?’ That kind of thing,” he said.

“And, obviously, I am not. I mean, I will die eventually, but not over a dermatological issue.”

Flaherty said he informed Prime Minister Stephen Harper of his condition and treatment last year before Christmas.

Some facts about bulbous pemphigoid:

WHAT IT IS: A skin condition that causes large fluid-filled blisters to form on the skin. The blisters, called bullae, typically form on the trunk, thighs, arms, in the groin and armpits and sometimes in the mouth. The blisters often form at creases in the skin. They can break open and form open sores or ulcers. Skin infections can result.

THE SYMPTOMS: In addition to the blisters, symptoms can include severe itching, rashes and bleeding gums.

THE CAUSE: Unknown. It is an auto-immune condition that occurs when the immune system attacks a thin layer of tissue under the outer layer of the skin. While a trigger isn’t generally identified, some cases are linked to previous use of some medications or exposure to UV light therapy or radiation treatment for cancer.

WHO GETS IT: It is mainly seen in people over 60. Though rare, the risk of developing the condition increases with age.

THE TREATMENT: Doctors often prescribe corticosteroids; Flaherty is on one, prednisone. Drugs to suppress the immune system and anti-inflammatory drugs may also be used.

THE PROGNOSIS: The condition can be life-threatening in older people in poor health. But it generally responds well to treatment and it can go into remission. Most people who suffer from the condition can eventually stop their drug regimen, but the disease sometimes returns.

Information sources: The Mayo Clinic and PubMed Health.