Shingles

What is shingles?

Shingles is an infection caused by reactivation of the varicella-zoster virus, which also causes chickenpox. After a chickenpox infection, the virus remains dormant in nerve cells and can reactivate later in life, producing a painful rash and other symptoms.

What causes shingles?

  • Virus reactivation

    The varicella-zoster virus travels from nerve cell clusters to the skin when it becomes active again.

  • Aging

    Immune defenses weaken with age, making reactivation more likely in older adults.

  • Weakened immune system

    Cancer treatments, immunosuppressive drugs, HIV/AIDS, and other conditions can trigger reactivation.

  • Stress

    Severe emotional or physical stress can impair immunity and allow the virus to reactivate.

  • Direct contact

    Fluid from shingles blisters can infect someone who never had chickenpox or the vaccine, causing chickenpox, not shingles.

What are the symptoms?

Local symptoms

  • Burning, tingling, numbness, or intense pain in one dermatome (skin segment)
  • Red rash that appears a few days after pain begins
  • Fluid-filled blisters that burst and crust over
  • Itching in the affected area

Systemic symptoms

  • Fever
  • Headache
  • Fatigue
  • Sensitivity to light
  • Upset stomach

Complications

  • Postherpetic neuralgia: severe nerve pain lasting months after rash heals
  • Ophthalmic zoster: shingles around the eye can threaten vision
  • Secondary bacterial infection of the blisters
  • Rarely, encephalitis, hearing loss, or death in immunocompromised people

How is shingles diagnosed?

  • Clinical evaluation

    Diagnosis by history of chickenpox and characteristic unilateral rash in a dermatomal pattern.

  • Polymerase chain reaction (PCR)

    Swab of blister fluid to detect varicella-zoster virus DNA; most sensitive test.

  • Direct fluorescent antibody (DFA)

    Less sensitive than PCR, uses labeled antibodies to detect viral antigens.

How is shingles treated?

Antiviral medications

  • Acyclovir (Zovirax)
  • Valacyclovir (Valtrex)
  • Famciclovir (Famvir)

Pain management

  • Over-the-counter analgesics: acetaminophen, ibuprofen
  • Prescription opioids for severe pain
  • Topical agents: lidocaine patches, capsaicin cream
  • Neuropathic pain drugs: amitriptyline, gabapentin

Supportive care

  • Keep rash clean and dry
  • Cool compresses to soothe itching
  • Loose clothing to avoid irritation
  • Rest and stress reduction

How can shingles be prevented?

The recommended vaccine is two doses of Shingrix for adults 50 years and older. It provides strong protection and reduces the risk of complications. Zostavax is no longer used in the United States.

Sources

  • Centers for Disease Control and Prevention. Shingles (Herpes Zoster). Accessed May 6, 2024.
  • National Institute on Aging. Shingles. Accessed May 6, 2024.
  • National Institute of Neurological Disorders and Stroke. Shingles Information Page. Accessed May 6, 2024.
  • Centers for Disease Control and Prevention. Shingrix Recommendations. Accessed May 6, 2024.
  • American Academy of Dermatology. Shingles. Accessed May 6, 2024.