See Herpes Zoster and Shingles.
This condition most commonly affects the ill or the elderly patient. It is usually on one side of the body only for example one side of the face or one side of the trunk. The condition starts with pain and tingling followed a few days later by a rash which blisters and becomes even more painful. Specialist assessment and anti-viral treatment is usually indicated. Early diagnosis and treatment can prevent a painful follow on disease affecting nerve endings. Expert consultation is available here.
by Dr John Ashworh