Shingles, also called herpes zoster, is a viral skin infection that creates a painful skin rash. It’s caused by the varicella-zoster virus, the same virus that causes chickenpox. Anyone who has had chickenpox can get it. After the chickenpox infection is over, the virus remains in your nervous system, dormant until it is reactivated as shingles.

The rash can appear red, dark pink, dark brown, or purplish, depending on your skin tone. It usually occurs on only one side of the body. It typically travels along from your spine along one or two spinal nerves, affecting a specific dermatome. A dermatome is an area of skin that a spinal nerve supplies.

This is why shingles is usually characterized by a rash as a stripe of blisters, typically on the torso, neck, or face.

Disseminated shingles is a complication of shingles where the rash covers a wider area, more than 20 lesions besides the main rash and affecting more than one or two of the body’s 31 pairs of spinal nerves. This complication affects three or more dermatomes.

According to research from 2023, disseminated shingles may affect other organs besides your skin. If untreated, this may lead to hepatitis or encephalitis, making this condition potentially life-threatening.

People with disseminated shingles may require hospitalization to receive intravenous antiviral medication and other treatments.

The symptoms of shingles, including disseminated shingles, include:

  • a painful rash with blisters that may itch or tingle, which appears on only one half of your body and scabs over in 7 to 10 days
  • itching, tingling, pain, or fever several days before a rash appears
  • upset stomach
  • headaches
  • sensitivity to bright light

While the rash usually appears in a line and only to one side of the body, disseminated shingles:

  • will include rashes in several places
  • cover a wider area
  • may cross the midline of the body

Anyone who has had chickenpox can get shingles. A definitive cause for virus reactivation has not been identified, but risk factors include:

About 50% of shingles cases affect people who are 60 years old or above, and the risk of shingles becomes greater at 70 years or above. But it can affect younger people as well.

Disseminated shingles affects about 15% to 30% of people with compromised immune systems, and about 2% of all people.

If you suspect you have shingles, it’s important to see a doctor as soon as possible. Early detection and treatment is crucial to lessening the severity of symptoms and preventing long-term complications, which include:

  • postherpetic neuralgia (PHN), which is long-lasting pain even after shingles clears up
  • the involvement of other organs like your lungs
  • hepatitis
  • encephalitis

The American Academy of Dermatology recommends visiting a healthcare professional within 3 days of symptom onset for effective treatment.