BOSTON -- From the age of 7, a local woman suffered from a condition that nearly killed her as an adult.

As News Center 5's Heather Unruh reported Tuesday, it took doctors more than three decades to reach a diagnosis.

Medical Mystery Solved In North Attleboro

For most of her life, Janet Long wondered what was making her so sick.

"I was age 7 when I can remember having stomach pains," said Long, of North Attleboro, Mass. "Mostly in high school I started experiencing a lot more difficulty. I would have a lot more pain, vomiting and diarrhea."

Long's symptoms got worse in college and into adulthood.

"I ended up with a very severe episode with internal bleeding and ended up in the ER. And then hospitalized in the ICU and underwent exploratory surgery and they didn't find anything there," she said. "I heard a number of different diagnoses."

At 40, a blood test revealed Long has a rare, life-threatening disease called hereditary angioedema. Only about 15,000 people in the U.S. have been diagnosed with the condition. It can cause swelling of the hands, feet, face and stomach.

"The symptoms of swelling can be mistaken for a lot of other things. And the disease itself has not been really well-known. And all those factors together have made it difficult to diagnose this disease," said Dr. Aleena Banerji, an allergist and immunologist with Mass General Hospital.

While Banerji has not treated Long, she has treated 10 to 15 patients with the same condition in the last five years. She said until now there has been no good treatment, which is why patients are excited about a newly approved FDA drug, Cinryze, to help prevent attacks.

"This drug would replace a new missing protein in the blood called CI inhibitor. It can be given as I.V.," Banerji said.

Long has been fighting to get this treatment approved in the U.S. for 10 years. She's excited to start infusions soon.

"It saves lives, and we're thrilled that it's finally available in the U.S.," she said.