The varicella-zoster virus (VZV) is the underlying cause of both chickenpox and the illness known as shingles, or herpes zoster, in older adults. While the initial infection with VZV during childhood causes the itchy, blister-like rash of chickenpox, the virus does not leave the body after recovery. Instead, it retreats and lies dormant in the nervous system, specifically in nerve roots near the spinal cord and brain. Years or even decades later, the virus can reactivate, causing the painful, localized rash that older individuals experience.
Why the virus reactivates as shingles
The reactivation of VZV as shingles is primarily linked to a decline in immunity. As people age, their immune system naturally weakens, making it less effective at keeping the dormant virus in check. This allows the virus to travel down the nerve pathways to the skin, causing the characteristic shingles rash. Other factors that can weaken the immune system and increase the risk of shingles at any age include:
- Stress: Severe mental or physical stress can lower immune function.
- Immunosuppressive medications: Drugs used for organ transplants or conditions like rheumatoid arthritis can increase risk.
- Chronic illness: Conditions such as HIV/AIDS and certain cancers (like leukemia and lymphoma) compromise the immune system.
- Cancer treatments: Chemotherapy and radiation therapy are known to lower a person's resistance to diseases.
Shingles symptoms and how they differ from chickenpox
For many older adults, the first signs of shingles are pain, tingling, burning, or itching that appears days before the rash. This pain, which can range from mild to severe, is a key differentiator from the generalized itchiness of childhood chickenpox. Once the rash appears, it is a hallmark sign of shingles.
The progression of the shingles rash
- Early stage: Red patches of skin form, accompanied by burning, tingling, or pain.
- Blistering: Within a few days, fluid-filled blisters appear on the reddened skin.
- Crusting: The blisters begin to dry out and scab over, typically within 7 to 10 days.
- Healing: The scabs fall off, and the rash usually clears within 2 to 4 weeks.
In addition to the rash and localized nerve pain, some people with shingles may experience other flu-like symptoms, including fever, headache, chills, and an upset stomach. The location of the rash is also distinctive, typically appearing as a single stripe on one side of the body, wrapping around the torso or appearing on one side of the face.
Shingles vs. chickenpox: Key differences
| Feature | Shingles (Herpes Zoster) in Older People | Chickenpox (Varicella) in Children |
|---|---|---|
| Cause | Reactivation of the varicella-zoster virus (VZV) that was dormant after a previous chickenpox infection. | Primary infection with the varicella-zoster virus (VZV). |
| Symptom Type | Often starts with a localized, intense pain or tingling sensation before a rash appears. | The defining symptom is a generalized, itchy rash that can appear all over the body. |
| Rash Pattern | A single stripe of painful, blistering rash on one side of the body or face, following nerve pathways. | Widespread, small red bumps and fluid-filled blisters that can number in the hundreds. |
| Contagiousness | A person with shingles can spread the virus to a non-immune person (who will then develop chickenpox), but it is less contagious than chickenpox and only spread through direct contact with open blisters. | Highly contagious and can be spread through respiratory droplets (coughing or sneezing) as well as direct contact with blisters. |
| Risk Group | Primarily affects adults over 50 and those with weakened immune systems. | Primarily affects children, though adults can get it too. |
| Complications | Postherpetic neuralgia (PHN), vision loss, and other serious issues are more common in older adults. | Less common in children, but can include pneumonia or other infections. |
Potential complications of shingles in older adults
The most common and dreaded complication of shingles for older people is postherpetic neuralgia (PHN), a condition where severe nerve pain persists for months or even years after the rash has healed. PHN can be debilitating, impacting a person's daily life, mood, and sleep.
Other serious complications can include:
- Vision Loss: Shingles on the face, particularly near the eye, can cause painful infections that may lead to permanent vision loss if not treated immediately by a doctor.
- Neurological problems: In rare cases, shingles can lead to brain inflammation (encephalitis), facial paralysis, or problems with hearing or balance.
- Skin infections: If the blisters are not kept clean, they can become infected with bacteria.
- Ramsay Hunt syndrome: When the virus affects the facial nerve near one ear, it can cause facial paralysis, ear pain, and hearing loss.
Prevention and treatment
Vaccination is the most effective way to prevent shingles and its complications in older adults. The CDC recommends two doses of the recombinant zoster vaccine (Shingrix) for healthy adults 50 and older. The vaccine is also recommended for adults 19 and older with weakened immune systems.
If you suspect you have shingles, it is crucial to see a healthcare provider as soon as possible, ideally within 72 hours of the rash appearing. Early treatment with antiviral medications such as acyclovir, valacyclovir, or famciclovir can shorten the duration of the illness and reduce the severity of symptoms. Pain relievers can also help manage the discomfort.
By understanding the causes, symptoms, and prevention methods for shingles, older adults and their families can take proactive steps to protect their health and well-being. Getting the shingles vaccine is the single most important action to take to avoid this painful and potentially debilitating illness.
For more information on shingles and its prevention, you can visit the CDC's Shingles website.
Conclusion
The reactivation of the varicella-zoster virus, which caused chickenpox in childhood, is known as shingles, or herpes zoster, in old people. As the immune system declines with age, the dormant virus can cause a painful, blistering rash that typically affects one side of the body. This can lead to serious complications, most notably postherpetic neuralgia. Fortunately, the highly effective shingles vaccine, Shingrix, can help prevent this illness and its potential long-term effects. For those who do contract shingles, early treatment with antiviral medications is key to managing symptoms and reducing the risk of complications.
