Your GP will normally be able to diagnose shingles from your symptoms and the appearance of your rash. Testing is not usually necessary.
It is uncommon for someone with shingles to be referred to a specialist for further assessment and treatment, but your GP may consider seeking specialist advice or referring you if:
You may also be referred to a specialist if you have an unusually persistent case of suspected shingles that is not responding to treatment, or if you have been diagnosed with the condition more than twice.
Who you are referred to will depend on your circumstances. It could be:
SOURCE: NHS UK
http://www.nhs.uk/Conditions/Shingles/Pages/Diagnosis.aspx