Having a medical issue, which others cannot see, can be challenging for sufferers, and one woman has revealed how her own "invisible illness" derailed her pursuit of a new career.

Paula O'Neill, a 25-year-old former Emirates cabin crew member and model from Scotland, recently told the Sunday Post that having the inflammatory bowel disease, ulcerative colitis has completely altered her appearance and put her out of work for several months. The notoriously uncomfortable condition initially caused her to use the bathroom up to 40 times per day, making her "frail and ill." Once she started taking prescribed steroids to fix the problem, however, she put on a significant amount of weight. The condition has "taken over [her] life" as she has spent so much time in and out of the hospital. She was working towards becoming a nurse when she started feeling sick from the illness.

“People who know me didn’t know what to think. I’m sure some of them thought, ‘Paula’s really let herself go!'" O'Neill, who was a finalist for the Miss Scotland competition, told the publication. “One minute I’m far too thin and the next I’m a big girl, but it’s the medication that caused it and, believe me, it’s a price well worth paying.”

She said that even though she was never bullied for her changing appearance, she got word that people were talking about why she looked different.

O'Neill said she feels that having an inflammatory bowel disease is a "taboo subject" and that "some people just think you’re lazy or being over-dramatic" because it's an invisible illness.

Many commenters, however, have thanked O'Neill for shedding light on this particular digestive issue:

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O'Neill added in a comment on Facebook that even though her health is more important to her than looks, experiencing such a drastic change in her appearance was quite an adjustment:

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"[M]y looks and body changing (to me dramatically to the point people didn't recognize me) ... did change my life and confidence a lot," she wrote.

According to the Crohn's & Colitis Foundation of America, as many as 1.6 million Americans suffer from inflammatory bowel diseases, and the majority of these people are diagnosed before turning 35. There are ways to improve the effects of inflammatory bowel diseases, but ultimately they are not curable conditions. People with inflammatory bowel diseases are at a greater risk of colon cancer and blood clots, the Crohn's & Colitis Foundation of America found.

Last year, ATTN: interviewed a 24-year-old man named Ste Walker who went viral for sharing his own experiences with the quiet discomfort of inflammatory bowel diseases on Facebook:

"I am sick of people saying [to] me, 'You don't look poorly,' or 'Crohn's isn't that bad,'" he told ATTN: last year. "I bumped into someone I know down at the hospital shop, and he said, 'What are you still doing here? You look totally fine,' and that just made me blow my top, because I'd kept it all bottled inside. So I had a rant on [Facebook]. 'Why should disability have a 'face'? It shouldn't at all.'"

Read the full Sunday Post story here.