Amy Schumer reveals she has Cushing Syndrome after fans expressed concern over her appearance

Amy Schumer has revealed that she's been diagnosed with an extremely rare condition.

The Trainwreck and Life & Beth star has recently had to respond to people's unkind comments about her 'puffier' face.

Schumer recently featured on The Tonight Show with Jimmy Fallon to promote the second series of Life & Beth, where people raised questions about her appearance.

"Thank you so much for everyone's input about my face," she penned on Instagram earlier this month.

"I've enjoyed feedback and deliberation about my appearance as all women do for almost 20 years. And you're right it is puffier than normal right now."

She went on to explain that she had some 'medical and hormonal' things which may have affected how she looks at the moment, adding that she is 'okay'.

Further details of her condition have since been revealed, and it's said that the 42-year-old has Cushing Syndrome.

The illness affects approximately 13 per million people annually, and typically occurs in people aged 25 to 40, as per the National Organization of Rare Diseases (NORD).

It defines the illness as 'a rare endocrine disorder, characterized by a variety of symptoms and physical abnormalities that occur as a result of excessive amounts of the hormone cortisol, a vital glucocorticoid'.

Some symptoms include weight gain in the face, bone pain, frail skin that bruises easily, and acne.

It's believed that her Cushing Syndrome was brought on by getting steroid injections in high doses.

Speaking to Jessica Yellin for her News Not Noise newsletter, Schumer was asked how she's feeling in light of her diagnosis.

"I feel reborn," said Schumer. "There are a few types of Cushing. Some that can be fatal, require brain surgery or removal of adrenal glands.

"While I was doing press on camera for my Hulu show, I was also in MRI machines four hours at a time, having my veins shut down from the amount of blood drawn and thinking I may not be around to see my son grow up.

"So finding out I have the kind of Cushing that will just work itself out and I'm healthy was the greatest news imaginable. It has been a crazy couple weeks for me and my family."

While the comments she received about her appearance weren't particularly nice, the comedian admitted that it's how she realized that something was wrong.

As to why she's decided to publicly share her diagnosis, Schumer said she wants to 'advocate for women's health'.

"I want so much for women to love themselves and be relentless when fighting for their own health in a system that usually doesn't believe them," said the I Feel Pretty star.

"[...] I am extremely privileged to have the resources I have for my health and I know it's not that way for most people. I am grateful and want to use my voice to continue to fight for women."