Herpes zoster, "shingles", is caused by the varicella-zoster virus, which belongs to herpesviruses. The latent post-varicella infection may be aggravated by any disturbance in the health of the (usually elderly) patient. The first symptom is pain, then clear vesicles on red background appear, later the content of the vesicles becomes turbid. The risk of after-pain may be diminished by early oral antiviral therapy.