By DAILY MAIL REPORTER
The smile is never off her beautiful face.
But the pressure on Britney Spears as a judge in the latter stages of Simon Cowell's X Factor seems to be causing the 31-year-old stress that belies her beatific countenance.
The Lucky star is believed to suffer from psoriasis, according to the National Enquirer.
And she stepped out at the X Factor premiere party in Los Angeles on Thursday night looking polished and put together in a form-fitting leather dress with flower detail.
But red patches on her left ankle and right heel were impossible to miss.
A source told the National Enquirer after a break-out at the beginning of her tenure on the talent show in September: 'Britney has had the skin condition for a long time, but it only flares up when she's under extreme pressure.
'Now she can't seem to stop scratching and picking at the sores. She has a psoraisis skin cream, but she says it burns, so she stopped using it.'
The causes of psoriasis are not fully understood but genetics play a strong role. It can appear on any part of the body and is often itchy.
The condition occurs when skin cells grow at an excelled rate due to the immune system sending out faulty signals.
It appears on the skin’s surface as red and white scaly patches, although some patients show no dermatological signs and it is not contagious.
And Britney isn't the only star said to suffer from the autoimmune disease.