Fleece and soft-shell jackets are a no-no if doctors want to make a good impression with patients, a US survey suggests.

Clinicians who wear casual attire are perceived as less experienced, less professional and not as friendly as those who wear white coats, according to the survey conducted by doctors from the John Hopkins University School of Medicine in Baltimore in Maryland.

But female doctors face the harshest criticism, with patients ranking them as less professional than their male counterparts regardless of their outfit, underscoring ongoing gender bias among patients, they said.

For the study the doctors asked 487 adults (mean age 36) to undertake a survey featuring photos of deidentified models wearing scrubs or business attire with or without a white coat, fleece jacket or soft-shell jacket over the top.