After the outbreak of chicken pox, the varicella-zoster virus lies dormant in the nerve cells of the brain or spine. About a quarter of the people who have had chicken pox will contract shingles decades after having that initial infection. Shingles is most common in people over the age of 50 and people with weakened immune systems due to medication or other diseases, including cancer and AIDS.
Shingles usually results in a small patch of lesions, often in a striped formation. It's generally on the torso or face but can spread to the eyes (herpes zoster ophthalmicus) and potentially cause glaucoma. The lesions are itchy and painful just like those with chicken pox, but they often resemble hives rather than the characteristic chicken pox blisters.
Prior to developing the rash, people with shingles may experience other symptoms: fevers, headaches, burning, tingling, numbness and extremely sensitive skin. The rash and the accompanying symptoms usually last for a few weeks to a month. Some people have scarring and discoloration at the rash site for the rest of their lives. Others have zoster sine herpete -- all of the other symptoms without the rash.
People with shingles can also experience nerve damage following the outbreak. Post-herpetic neuralgia, caused by VZV at the site of the rash, can result in chronic extreme pain, sensitivity and numbness. In rare cases, shingles can also cause inflammation disorders such as encephalitis or myelitis as well as paralysis (usually temporary) and hearing loss.
Shingles patients can take pain relievers and anti-itching medications to help with the rash. They're also treated with one of the antiviral medications and steroids to reduce inflammation. You can't give shingles to someone else, although people who haven't had chicken pox or the vaccine can acquire VZV if they come in direct contact with the blisters.
A vaccine specifically to prevent shingles was approved by the FDA in 2006. Zostavax is essentially a stronger version of Varivex, the vaccine to prevent chicken pox. In clinical trials it was shown to reduce the incidence of shingles by more than 50 percent and reduce the incidence of post-herpetic neuralgia by nearly 67 percent [source: New England Journal of Medicine]. It's recommended for all adults age 60 or over, including those who have already had a shingles outbreak.
Not all types of herpes cause blisters or lesions. In the next section, we'll check out the Epstein-Barr virus.