Shingles: What disease occurs when the latent chickenpox virus reactivates in older adults?

Approximately one in three people in the United States will develop shingles in their lifetime. This painful viral infection, caused by the same virus that causes chickenpox, occurs when the latent chickenpox virus reactivates in older adults and those with weakened immune systems. This guide explores the details of this condition, its symptoms, risk factors, and preventative measures.

Quick Summary

Shingles, also known as herpes zoster, is the painful viral infection that results from the reactivation of the varicella-zoster virus, which lies dormant in the body after a person has recovered from chickenpox. It is most common in adults over 50.

Key Points

• Reactivation Cause: The varicella-zoster virus, dormant after a chickenpox infection, reactivates, causing shingles, especially in older adults due to a weakened immune system.

• Symptoms: Early symptoms include pain, tingling, or itching, followed by a characteristic painful, blistering rash in a stripe on one side of the body.

• Long-term Pain: A common complication, postherpetic neuralgia, causes persistent nerve pain in the affected area long after the rash disappears, with risk increasing with age.

• Prevention: The most effective prevention is the shingles vaccine (Shingrix), recommended for adults over 50.

• Treatment: Antiviral medications started early can shorten the infection's duration and severity.

• Complications: Severe complications can include eye infections leading to vision loss, encephalitis, or other neurological issues, underscoring the need for timely medical attention.

• Infectious Period: The virus can be spread to those without prior chickenpox exposure via direct contact with the fluid from the blisters, causing chickenpox in them, not shingles.

Understanding the Reactivation of the Varicella-Zoster Virus

The varicella-zoster virus (VZV) is the underlying cause of both chickenpox and shingles. Following a childhood chickenpox infection, the body successfully fights off the visible illness, but the virus doesn't leave the body. Instead, it travels along nerve pathways and settles in nerve tissue near the spinal cord and brain, where it remains dormant or latent for decades. For most of a person's life, a healthy immune system keeps the virus suppressed and inactive. However, as individuals age, their immune systems naturally weaken, a process known as immunosenescence. This decline in cell-mediated immunity can allow the dormant VZV to reactivate, causing it to travel back down the nerve pathways and emerge on the skin as a characteristic, painful rash.

Why Older Adults are More Susceptible to Shingles

While anyone who has had chickenpox can develop shingles, the risk increases significantly with age. This is primarily due to the natural decline of the immune system over time. Starting around age 50, the immune system's ability to keep the varicella-zoster virus under control wanes, making reactivation more likely.

Key factors contributing to the increased risk in older adults include:

• Immunosenescence: The age-related decrease in T-cell function weakens the body's specific defense against VZV.
• Co-morbidities: Other age-related health conditions, such as diabetes or chronic lung disease, can further compromise the immune system.
• Medical treatments: Treatments that suppress the immune system, such as chemotherapy or long-term steroid use, also increase the risk.
• Stress: Both physical and mental stress can temporarily weaken the immune system, acting as a trigger for reactivation.

The Symptoms and Progression of Shingles

The onset of shingles typically follows a predictable pattern, though not every individual will experience all symptoms. The disease is characterized by a localized, painful rash that often appears in a single stripe on one side of the body.

Early (Prodromal) Phase: This phase occurs days to weeks before the rash appears and includes symptoms like:

• Burning, tingling, or numbness in a specific area of the skin.
• Localized pain, itching, or sensitivity to touch.
• Systemic symptoms such as fever, headache, chills, and fatigue.

Active (Rash) Phase: Following the prodromal phase, a red, blotchy rash develops in the affected area. This rash quickly evolves into fluid-filled blisters that eventually dry out, crust over, and scab. During this period, the fluid in the blisters is highly infectious.

Late (Recovery) Phase: Once the blisters have crusted over, the risk of spreading the virus decreases. However, the pain associated with the infection can persist long after the rash has healed. This complication, known as postherpetic neuralgia (PHN), affects about 1 in 10 people who get shingles, and its likelihood increases with age.

Potential Complications of Shingles

Beyond the painful rash and postherpetic neuralgia, shingles can lead to more serious complications, especially in older adults. Prompt treatment is critical to minimize these risks.

• Ophthalmic Shingles: When shingles affects the nerves around the eye, it can cause painful eye infections, potentially leading to vision loss.
• Neurological Problems: In some cases, shingles can lead to inflammation of the brain (encephalitis), facial paralysis (Ramsay Hunt syndrome), hearing or balance issues, and in rare cases, stroke.
• Bacterial Skin Infections: Improper care of the blisters can result in a secondary bacterial skin infection.
• Disseminated Zoster: For individuals with severely weakened immune systems, the rash can spread across the body, similar to chickenpox, affecting internal organs.

Prevention and Treatment Strategies

Prevention is the most effective strategy for managing shingles in older adults. The development of a safe and effective vaccine has significantly reduced the incidence and severity of the disease.

Vaccination: The Centers for Disease Control and Prevention (CDC) recommends the shingles vaccine (Shingrix) for all adults aged 50 and older. The vaccine is given in two doses and is highly effective at preventing shingles and its complications, including postherpetic neuralgia.

Treatment: If shingles does occur, early treatment with antiviral medications can shorten the duration and severity of the illness.

• Antivirals: Medications like acyclovir, valacyclovir, and famciclovir are most effective when started within 72 hours of the rash's onset.
• Pain Management: Over-the-counter pain relievers, prescription pain medication, or topical pain patches may be used to manage nerve pain.
• Home Care: Keep the rash clean and dry, use cool compresses, and wear loose-fitting clothing to minimize irritation.

Shingles vs. Postherpetic Neuralgia

While related, shingles and postherpetic neuralgia (PHN) are distinct conditions. Understanding the difference is crucial for proper management, especially in older adults.

Feature	Shingles	Postherpetic Neuralgia (PHN)
Timing	Acute phase of VZV reactivation, lasting weeks	Pain that persists for months or years after the shingles rash has cleared
Symptoms	Painful, blistering rash in a dermatomal pattern; tingling, numbness, itching	Chronic nerve pain, often described as burning, sharp, or stabbing, in the area where the rash was
Cause	Reactivation of the varicella-zoster virus from latent state	Damaged nerve fibers from the shingles infection continue to send confused pain signals to the brain
Risk Factors	Age over 50, weakened immune system, stress, certain medical conditions	Primarily associated with age; older patients with shingles have a higher risk of developing PHN
Treatment	Antiviral medications (e.g., acyclovir, valacyclovir) started early	Pain management strategies, including topical treatments, nerve blocks, and specialized pain clinics

Conclusion: Proactive Care is Key for Older Adults

What disease occurs when the latent chickenpox virus reactivates in older adults? The answer is shingles, a condition that can cause significant pain and serious complications. Given that the risk increases with age, it is a crucial concern for senior health. While the characteristic rash and nerve pain are debilitating, the availability of highly effective vaccines, like Shingrix, means that shingles is largely preventable. For those who do experience an outbreak, early diagnosis and treatment are essential for managing symptoms and reducing the risk of developing long-term pain from postherpetic neuralgia. Seniors and their caregivers should consult a healthcare provider to discuss vaccination and other preventive measures, ensuring a higher quality of life and peace of mind. For more information, the Centers for Disease Control and Prevention (CDC) provides extensive resources on shingles prevention and care at https://www.cdc.gov/shingles/index.html.

References

• Shingles (Herpes Zoster). CDC, 2024. https://www.cdc.gov/shingles/hcp/clinical-overview/index.html
• Shingles (Herpes Zoster): Causes, Symptoms & Treatment. Cleveland Clinic, 2024. https://my.clevelandclinic.org/health/diseases/11036-shingles
• Shingles - Symptoms & causes. Mayo Clinic, 2022. https://www.mayoclinic.org/diseases-conditions/shingles/symptoms-causes/syc-20353054
• What doctors wish patients knew about the shingles virus. AMA, 2023. https://www.ama-assn.org/public-health/prevention-wellness/what-doctors-wish-patients-knew-about-shingles-virus
• Herpes Zoster in the Older Adult. NIH, 2017. https://pubmed.ncbi.nlm.nih.gov/29079160/
• Shingles (herpes zoster). World Health Organization (WHO), 2025. https://www.who.int/news-room/fact-sheets/detail/shingles-(herpes-zoster)
• Recent Issues in Varicella-Zoster Virus Latency. MDPI, 2021. https://www.mdpi.com/1999-4915/13/10/2018
• Varicella zoster virus latency. PMC (NIH), 2011. https://pmc.ncbi.nlm.nih.gov/articles/PMC3118253/
• Neurological Disease Produced by Varicella Zoster Virus Reactivation Without Rash. PMC (NIH), 2011. https://pmc.ncbi.nlm.nih.gov/articles/PMC3076592/
• Modeling Varicella Zoster Virus Persistence and Reactivation. Frontiers, 2019. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.01634/full

Frequently Asked Questions

What is the virus that causes chickenpox and shingles?

Both chickenpox and shingles are caused by the varicella-zoster virus (VZV). After a person recovers from chickenpox, the virus remains inactive in the body and can reactivate later in life as shingles.

Why does shingles primarily affect older adults?

Shingles most commonly affects older adults because the immune system weakens with age, a process called immunosenescence. This natural decline in immune function makes it easier for the dormant varicella-zoster virus to reactivate.

Is shingles contagious?

A person with shingles cannot transmit shingles directly to another person. However, they can spread the varicella-zoster virus through direct contact with the fluid in the blisters, which can cause chickenpox in someone who has not had chickenpox or the chickenpox vaccine.

What is postherpetic neuralgia?

Postherpetic neuralgia (PHN) is a potential complication of shingles characterized by persistent nerve pain that continues for months or even years after the shingles rash has disappeared. It is the most common complication of shingles.

Is there a vaccine to prevent shingles?

Yes, there is a highly effective vaccine called Shingrix that is recommended for adults aged 50 and older to prevent shingles. The vaccine can significantly reduce the risk of developing shingles and its long-term complications.

What should I do if I think I have shingles?

You should see a healthcare provider as soon as possible, ideally within the first 72 hours of the rash's onset. Early treatment with antiviral medications can help shorten the infection and reduce the risk of complications.

Can I get shingles more than once?

Yes, it is possible to get shingles more than once. While most people experience only one episode, recurrence can happen, particularly in individuals with weakened immune systems.