Herpes Zoster is caused by Varicella-zoster virus.
Varicella-zoster virus causes two distinct clinical entities: varicella, or chickenpox, and herpes zoster, or shingles. Herpes Zoster presents as a type of skin rash accompanied by severe nerve pain.

Herpes zoster disease, is the consequence of reactivation of latent VZV ( Varicella – zoster virus ) from the dorsal root ganglia. Herpes zoster occurs at all ages, but its incidence is highest (5 to 10 cases per 1000 persons) among individuals in the sixth through the eighth decades of life. It has been suggested that approximately 2 percent of patients with herpes zoster will develop a second episode of infection.

This disease is characterized by a one sided vesicular eruption on the line of a nerve and is associated with severe pain. The erythematous maculopapular rash changes rapidly into vesicular lesions. The onset of the disease starts usually with severe pain on the line of the nerve that is involved with the disease process. The eruption may remain few in number or may continue to form for 3 to 5 days. The total duration of disease is generally between 7 and 10 days; however, it may take as long as 2 to 4 weeks for the skin to return to normal.

The disease may appear practically any place in the body. It may appear on the face (very common), tongue, mouth, and eye. It’s commonly seen on the one side of the chest.

If vesicles appear in the ear canal,  patients lose their sense of taste in the anterior two-thirds of the tongue while developing one sided facial palsy.

Post Herpetic Neuralgia is the most common complication of this disease. It’s seen most in the elderly patients or in immuno-compromised patients. This is a very troublesome pain persisting after the resolution of the disease process.

Treatment
Acyclovir, 800 mg per day for 7 to 10 days. Famciclovir, Valacyclovir are also used for herpes zoster. Other supportive measures may also be needed to manage pain and to prevent secondary infection of the eruptions.

Involvement of the eye needs timely care by ophthalmologist. Eye involvement can be troublesome when cornea is involved.