A recent study at Rice University and the University of Houston has pointed out that candidates with birthmarks, scars and other facial disfigurements.

Basically, interviewers get distracted by conspicuous scars and blemishes and are hence unable to remember the main content of the interview.
“When evaluating applicants in an interview setting, it's important to remember what they are saying,” Rice psychology professor Mikki Hebl said. “Our research shows if you recall less information about competent candidates because you are distracted by characteristics on their face, it decreases your overall evaluations of them.”
Source-Medindia