What is shingles? The common yet painful condition blighting Sen Feinstein explained

Democratic Senator Dianne Feinstein, felled earlier this year by a case of shingles, has experienced more severe health troubles than were previously known.

Sen Feinstein, 89 and facing calls to resign from several fellow Democratic lawmakers and progressive groups in California, returned to Washington after a months-long absence recovering from shingles.

The 50-year veteran of California politics was hospitalized in late February with the common disease, which is triggered by the same virus as chickenpox and can remain dormant in the body for years before becoming reactivated in older age.

She had a previously unreported case of encephalitis, a potentially severe condition in which the brain becomes inflamed and swells, causing temporary symptoms such as headaches and fever as well as long-lasting harms including memory or language troubles.

The shingles virus has also triggered vision and balance troubles as well as Ramsay Hunt syndrome leading to facial paralysis, which is typically curable.

Shingles can occur anywhere on your body. It typically looks like a single stripe of blisters that wraps around the left side or the right side of your torso. Photos shows a patient’s rash on their abdoment, courtesy of the Centers for Disease Control and Prevention (CDC)

In some cases, the rash occurs on one side of the face, which can affect the eye and cause vision loss. Photo courtesy of the CDC

Shingles causes a painful rash that can occur anywhere on the body and typically looks like a patch or stripe of blisters that wraps around the torso.

About one in three people in the US will develop shingles in their lifetime and many will survive it. It causes fewer than 100 deaths annually. 

But shingles death rates are approximately 10 times higher among people over 65 years old.

Shingles cannot be transmitted directly from person to person. Direct contact with someone’s blistery rash, which contains particles of the virus, can cause them to contract the varicella-zoster virus and get chickenpox.

The blisters typically scab over in a week to 10 days and fully clear up within a month with the help of antiviral medications. Adults 50 and older can also be vaccinated against shingles.

Most people who experience severe cases of shingles have compromised immune systems. 

Thirty percent of all shingles hospitalizations are in people with weak or compromised immune systems, such as those who have received organ transplants and are on immunosuppressing drugs.

While the rash will heal, shingles can leave behind severe pain in the nerves and skin where the rash was, a complication known as postherpetic neuralgia (PHN). 

Up to 18 percent of people who had shingles will experience painful PHN symptoms.

Post-shingles encephalitis, from which it is said the senator has recovered, can lead to fatigue, irritability, impaired concentration, seizures, hearing loss, memory loss and blindness in the long-term.

The encephalitis, as well as her facial paralysis, were triggered by the shingles virus. 

And when it comes to severity of symptoms and the recovery process, older patients tend to fare worse.

A study published last year in the journal Annals of Intensive Care found that out of 55 critically ill patients with the virus, more than a fifth were significantly disabled one year after being admitted to the intensive care unit.

While older people tend to have worse outcomes, doctors cannot say for certain why the virus that causes shingles is reactivated later in life. It is possibly due to age-related waning of the immune system.