This isn’t a guideline really, but an excellent booklet (I can’t link the actual booklet, but it’s easy to find on the above link). It is a one stop shop for all you need to know about STDs and sexual health. There’s far too much to summarise, but I would encourage you to spend 10 minutes scrolling through, so that you know what it covers. You can then refer back to it when you need.
BASHH | Sexually transmitted infections in primary care
10th May 2013 by Louise Hudman