Some patients might think about getting a second opinion after receiving advice or a diagnosis from a doctor, but is the availability of online social networking taking this to a new and concerning level?

In the web 2.0 era, indiscriminate ‘crowd-diagnosis’ may be overtaking blind faith in Dr Google, according to researchers in the US.

They have looked at how, since 2010, on the sharing and discussion site ­Reddit, increasing numbers of people have been asking strangers to help diagnose their diseases.

The researchers have specifically tracked a ‘subreddit’ that invites discussion about STIs. It comes at a time when STIs are at an all-time high in the US, while the number of patients visiting sexual health clinics are fewer than would be expected, the researchers say.