Anticonvulsant medication: Medication used in the treatment of seizures and epilepsy, and has been shown to be useful in the treatment of PHN.

Antiviral medication: A medicine that kills viruses or inhibits their ability to reproduce.

Appendicitis: Inflammation of the appendix.

Bacterial infection: Infection that can occur when bacteria affect a part of the body.

Blister: A raised bump in the skin that contains watery liquid.

Dermatome: A band of skin that receive sensations through a single nerve. Shingles usually affects one or more isolated dermatomes.

Disseminated zoster: Spread of the zoster virus throughout the body, reaching vital organs like the lungs. If not treated, disseminated zoster can lead to death from viral pneumonia or secondary bacterial infection.

Dormant: Existing in a hidden form. Present, or capable of living or developing in a host, without producing visible symptoms of disease.

Eruptive stage: With shingles, a rash and/or blisters appear during this stage.

Gallstone: A concentration of material formed in the gallbladder or bile duct.

Hutchinson's sign: Occurs when a shingles blister(s) appears on the tip of the nose, indicating that the varicella zoster virus has affected the nerve in the eye.

Immune system: A complex system in our bodies that is responsible for protecting us against infections and foreign substances.

Immunity: The state of being immune; a condition of being able to resist a particular disease.

Kidney stones: A mass of hard material in the kidney.

Nervous system: The collection of body tissues that record and distribute information by electrical and chemical signals. It includes the central (brain and spinal cord) and peripheral nervous systems.

Neurons: Nerve cells that receive and send electrical signals over long distances within the body.

Opioid medications: A narcotic medication that is used to relieve pain.

Ophthalmic zoster: The zoster virus invades the nerve in the eye (ophthalmic nerve), causing painful swelling of the eye. This inflammation can cause temporary blindness. Blisters on the nose may be a sign that the eye is infected with the shingles virus.

Outbreak: With shingles, an outbreak occurs when a rash and blisters appear on the skin.

Pleurisy: Inflammation of the pleural cavity, which is located in the chest.

Ramsay Hunt Syndrome: Occurs when the varicella zoster virus affects the facial nerve, causing intense ear pain, hearing loss, dizziness, and facial paralysis.

Postherpetic neuralgia (PHN): The most common complication of shingles. It occurs when the pain associated with shingles even after the rash is healed.

Prodromal stage: An early warning symptom of illness. With shingles, this involves numbness, itching, tingling, burning, or shooting pain, and fever, headaches, chills, and nausea before the skin rash appears.

Shingles: An acute infection caused by a reactivation of the varicella zoster virus, which also causes chicken pox. It usually occurs during adulthood after exposure to chicken pox in childhood. The chicken pox virus remains dormant in the body.

Varicella zoster virus: The virus that causes chicken pox and herpes zoster (shingles).

Virus: A microorganism, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and replicate itself.