Shingles represents reactivation of a previous infection with the varicella-zoster virus. Initial infection with the virus causes chickenpox. As the illness resolves, the viruses assume an inactive form in the nerves. Later in life, varicella-zoster viruses can reactivate, causing shingles. A painful, blistering rash following the path of the infected nerve characterizes an attack of shingles, also known as herpes zoster. Dangerous shingles complications may occur if the reactivated viruses attack and damage vulnerable tissues.
Herpes Zoster Ophthalmicus
Herpes zoster ophthalmicus is a reactivation of the varicella-zoster virus within the nerves of the eye, which can potentially cause permanent damage. The Centers for Disease Control and Prevention reports that approximately 10 to 25 percent of people with shingles have eye involvement. Various manifestations of herpes zoster eye involvement can occur, depending on the specific eye nerves affected. Infection and inflammation of the eyelid and inner surface of the eye may occur, causing redness, blistering, pain and swelling. Involvement of the cornea---the clear area at the front of the eye---may lead to ulcerated sores. The varicella-zoster virus can also infect the interior eye structures, including the retina---the surface that captures images envisioned by the eye and transforms them into signals transmitted to the brain. Herpes zoster ophthalmicus may cause scarring of the eye structures and permanent vision loss.
Ramsay Hunt Syndrome
The National Institute of Neurological Disorders and Stroke explains that reactivation of the varicella-zoster virus within the nerves in and around the ear causes Ramsay Hunt syndrome. Severe pain typically occurs deep in the ear. The external ear exhibits the typical rash of shingles. The Mayo Clinic notes that the affected ear often exhibits hearing loss. Involvement of the balance structures of the inner ear lead to vertigo---a phantom whirling sensation. Weakness of the facial muscles on the affected side causes drooping of the eye and mouth. An altered sense of taste may also occur. Pain in the affected structures may persist after the episode of shingles clears, a condition known as postherpetic neuralgia. Permanent hearing loss and facial weakness may occur in some people with Ramsay Hunt syndrome.
Encephalitis
The varicella-zoster virus can spread to the brain during an episode of shingles, causing viral encephalitis---inflammation of the brain. The National Institute of Neurological Disorders and Stroke notes that symptoms of viral encephalitis may include headache, fatigue, decreased consciousness, hallucinations, muscle weakness, loss of sensation in localized areas, impaired judgment, memory loss, confusion and seizures. Early treatment with antiviral medication reduces the risk for permanent brain injury.
References
- Centers for Disease Control and Prevention, MMWR: Prevention of Herpes Zoster
- American Family Physician; Evaluation and Management of Herpes Zoster Ophthalmicus; Saad Shaikh, M.D., Christopher N. Ta, M.D.; November 2002
- MayoClinic.com: Ramsay Hunt Syndrome Symptoms
- MayoClinic.com: Ramsay Hunt Syndrome Complications
- Patient UK: Herpes Zoster Oticus (Ramsay Hunt Syndrome)
