Herpes Zoster (Shingles) & Postherpetic Neuralgia
Shingles High-yield Verified · Sep 2026Herpes zoster (shingles) is a painful vesicular rash in one or two adjacent dermatomes caused by reactivation of latent varicella-zoster virus; postherpetic neuralgia is pain that persists in the area of the rash for more than 90 days after rash onset.
After chickenpox the virus sleeps in a sensory ganglion. When cell-mediated immunity wanes — with age, illness or immunosuppressive drugs — it reactivates, rides one nerve to the skin and causes pain, then a stripe of vesicles that stays on one side of the body. Contacts who never had chickenpox can catch chickenpox, not shingles. Pain lasting beyond 90 days is postherpetic neuralgia.
What’s going wrong in the body
The normal physiology, where it fails, and why the body’s compensation backfires.
01 Latent virus in a sensory ganglion wakes when cell-mediated immunity falls
[Shingles] "Herpes zoster (shingles) is caused by the reactivation of varicella-zoster virus (VZV), the same virus that causes varicella (chickenpox)." After chickenpox, the virus "remains dormant in the sensory ganglia of the cranial nerves or the dorsal root ganglia after a previous varicella infection."
Why it reactivates. "VZV latency is largely controlled by cell-mediated immunity, and reactivation is thought to result from the loss of this immune surveillance." CDC: "a person's risk for herpes zoster increases as their VZV-specific cell-mediated immunity declines. This decline in immunity can result from increasing age and medical conditions or medications that suppress a person's immune system." Still, "The reasons why VZV reactivates and causes herpes zoster are not well understood."
Why the rash is a one-sided band. "After reactivation, the virus replicates in neuronal cell bodies, and virions are shed from the cells and are carried down the nerve to the area of skin innervated by that ganglion. In the skin, the virus causes local inflammation and blistering. The pain caused by zoster results from virus-associated inflammation of affected nerves." NIA: shingles stays "on just one side of the body or face because the reactivated virus travels in a specific nerve."
02 Spread: contacts catch chickenpox, and precautions follow host and extent
What a contact catches. "People with active herpes zoster lesions can spread VZV. VZV causes varicella in people who never had chickenpox or those who didn't receive the varicella vaccine." NIA: a contact "will not get the symptoms of shingles yourself" — but "direct contact with fluid from a shingles rash can still spread the varicella-zoster virus."
How and until when. "Active herpes zoster lesions are infectious through direct contact with vesicular fluid; or breathing in virus particles from the blisters until they dry and scab over." "People with active herpes zoster lesions should cover their lesions; and avoid contact with susceptible people in their household and occupational settings until their lesions are dry and scabbed."
Hospital precautions (CDC Appendix A). Localized zoster in a patient "with intact immune system with lesions that can be contained/covered" → Standard precautions "Until lesions dry and crusted." "Disseminated disease in any patient" or "Localized disease in immunocompromised patient until disseminated infection ruled out" → Airborne + Contact + Standard for the "Duration of illness." "Susceptible HCWs should not enter room if immune caregivers are available."
03 The eye branch (HZO) and pain that outlasts the rash (PHN)
[HZO] "Herpes zoster ophthalmicus (HZO) occurs when the virus involves the ophthalmic division of the trigeminal cranial nerve." That branch supplies "the cornea, conjunctiva, sclera, iris, and eyelids," so eye disease is common — "eye disease develops in approximately 50% of cases." Vesicles on the tip of the nose (Hutchinson sign) indicate "nasociliary branch involvement of V1, which confers a higher risk for ocular involvement" — but "its absence does not exclude eye disease." "Because of the high risk of vision loss if not promptly recognized and treated, HZO is considered an ophthalmologic emergency."
[PHN] "PHN is the most common complication of herpes zoster. PHN is pain that persists in the area where the rash once was located; and continues more than 90 days after rash onset. PHN can last for months or even years." Nerve tissue shows "myelin and axon deficiency and atrophy of the dorsal horn in certain instances"; one theory is that "an unchecked inflammatory response at the neuronal level" reduces central inhibition of pain signals and promotes "peripheral sensitization via damaged nociceptors." StatPearls keeps the hedge: the mechanism "is not fully understood."
Who gets PHN. "Approximately 10% to 18% of people with herpes zoster will have PHN." "PHN is rare in people younger than 40 years old. The likelihood of PHN is also higher in people who experience more pain with the rash or have a large rash." Risk factors also include "advanced age, severe prodromal pain, severe pain during an attack, severe rash, and immunosuppression."
Causes & risk factors
Modifiable factors are teaching targets — the patient can act on them.
Signs & symptoms
Each finding tied to the mechanism that produces it — and the triage it calls for.
Diagnostics
Complications
Medications for this condition
Why each class is prescribed here — every card links to its full pharmacology page.
[Shingles] First-line — start early. CDC: "There are three preferred antiviral drugs available for the initial treatment of shingles": acyclovir, valacyclovir and famciclovir; they "accelerate the resolution of lesions; reduce the development of new lesions and viral shedding; and decrease the severity of acute pain." "Treatment is most effective within 72 hours of symptom onset"; the Valtrex label says "most effective when started within 48 hours of the onset of rash" and has "no data on treatment initiated more than 72 hours after onset." For HZO, treatment "should not be delayed while awaiting definitive diagnosis or ophthalmology follow-up." IV acyclovir is used for immunocompromised, disseminated or CNS/orbital disease. Acyclovir is 85% renally excreted and can cause crystal nephropathy — keep patients hydrated ("Adequate hydration should be maintained for all patients") and reduce doses in renal impairment. Whether antivirals prevent PHN is disputed: StatPearls (zoster) says antiviral therapy "helps prevent postherpetic neuralgia," while StatPearls (PHN) finds "no clear evidence" they reduce PHN incidence.
Prevention — Shingrix (recombinant, adjuvanted, nonlive). CDC recommends "2 doses of recombinant zoster vaccine (RZV) to prevent shingles and related complications in adults aged ≥50 years" and "for adults aged ≥19 years who are or will be immunodeficient or immunosuppressed" (the FDA label indication for at-risk adults starts at 18). Doses "separated by 2–6 months" (for immunocompromised adults who would benefit from a shorter schedule, the second dose "can be administered 1–2 months after the first"); if late, "Do not restart the vaccine series." Give it whether or not the person had shingles or Zostavax — but "you should not give Shingrix to patients who are experiencing an acute episode of herpes zoster." It is "not indicated for prevention of primary varicella infection (chickenpox)." Contraindicated after "a severe allergic reaction (e.g., anaphylaxis)"; label warns of a Guillain-Barré signal "during the 42 days following vaccination" and syncope.
[PHN] First-line systemic pain treatment. "Pharmacologically, first-line systemic treatments consist of anticonvulsants such as gabapentin and pregabalin." Both "require careful dose titration and monitoring for adverse effects such as sedation and cognitive impairment"; with reduced renal function, start "at a lower dose and titrated upward more slowly."
[PHN] "Tricyclic antidepressants such as amitriptyline and nortriptyline are also commonly used because of their analgesic properties; nortriptyline tends to be better tolerated." Caution in older adults: "The anticholinergic, antihistaminergic, and α-receptor–blocking adverse effects of TCAs must be considered because older adults are more susceptible."
Beyond medications
- Comfort care (NIA): "Wear loose-fitting, natural-fiber clothing." "Take an oatmeal bath or use calamine lotion to soothe your skin." "Apply a cool washcloth to your blisters to ease the pain and help dry the blisters." "Keep the area clean and try not to scratch the blisters so they don’t become infected or leave a scar."
- [PHN] Topical patches — "Topical therapies include 5% lidocaine and 8% capsaicin patches. Lidocaine patches provide localized pain relief with minimal systemic effects, making them suitable for older adults and patients with comorbidities." High-strength capsaicin is applied "under medical supervision." Opioids such as tramadol "are considered third-line because of concerns about adverse effects and dependency."
- [PHN] Multimodal care and referral — "No single superior treatment regimen exists; however, expert consensus suggests that multimodal therapy is likely the best approach." Pain specialists "should be consulted" when needed; provide "psychological support resources for patients experiencing depression or anxiety related to pain or vision loss."
- [HZO] Eye care — "Artificial tears, cold compresses, and analgesics may be employed"; topical antibiotic ointment may help prevent secondary infection. Avoid unsupervised steroids — "Prescribing topical or systemic steroids without concurrent antiviral coverage may exacerbate viral replication and ocular disease." Keep ophthalmology follow-up for "keratitis, uveitis, glaucoma, and retinal involvement."
- Coping (NIA) — "Do things that take your mind off your pain." "Get plenty of rest and eat well-balanced meals ." "Share your feelings about your pain with family and friends, and ask for their support."
Nursing considerations
The RN-specific layer — each action paired with the reason it matters.
How a real nurse thinks
The clinical-judgment loop, worked for a typical presentation — reasoning, not reference.
- 1 Recognize cues
A dermatomal vesicular rash after a painful prodrome — shingles — plus blisters on the forehead and eyelid with a red, gritty, blurry eye, in an older, steroid-treated patient, rash onset about 1 day ago, and a creatinine rise.
- 2 Analyze cues
Forehead and eyelid lesions mean the ophthalmic branch is involved — HZO, "an ophthalmologic emergency," even though the nose tip is clear ("its absence does not exclude eye disease"). Long-term prednisone makes him immunocompromised, so he needs airborne + contact precautions until dissemination is ruled out. He is within the 72-hour window. Age and the creatinine rise raise his risk of antiviral kidney injury and CNS effects.
- 3 Prioritize
Protect vision and start the antiviral now, isolate correctly, and protect the kidneys.
- 4 Generate solutions
Notify the provider for an urgent ophthalmology referral and an antiviral order without waiting for PCR; place airborne + contact + standard precautions and assign immune staff; encourage fluids and monitor creatinine, urine output and mental status; assess pain early to reduce PHN risk.
- 5 Take action
SBAR: 72-year-old on chronic prednisone with right T-dermatome zoster and new vesicles on the right forehead and eyelid, red gritty eye, blurred vision, rash onset about 24 hours ago, creatinine 1.4 from 1.0. Requesting antiviral now and urgent ophthalmology evaluation. Precautions posted; oral fluids encouraged.
- 6 Evaluate
Antiviral started within the 72-hour window; ophthalmology sees him the same day. Over the next days no new lesions appear outside the original dermatomes, urine output stays adequate, and he remains oriented. Before discharge he is taught to report vision change, eye pain, or pain persisting after the rash heals.
Scenario — you’re the nurse
Work each question before revealing the answer. Rationales explain the wrong options too.
A 72-year-old man taking long-term prednisone for polymyalgia rheumatica is admitted with 2 days of burning pain along the right side of his chest, followed yesterday by clusters of blisters in a band from his spine to his sternum. This morning he noticed a few blisters on his right forehead and upper eyelid, and his right eye feels gritty.
Q1 Multiple choice Which finding in this patient requires the most urgent action? - A. Vesicles along a right thoracic dermatome
- B. Blisters on the right forehead and eyelid with a red, gritty eye
- C. Burning chest pain before the rash appeared
- D. Temperature 37.9 °C
Reveal answer & rationale
Q2 Multiple choice Which precautions should the nurse implement for this patient? - A. Standard precautions only, because the rash is localized
- B. Contact precautions only
- C. Airborne + contact + standard precautions until disseminated infection is ruled out
- D. Droplet precautions for 24 hours after starting the antiviral
Reveal answer & rationale
Q3 Select all that apply Which actions are appropriate while he receives an oral antiviral? Select all that apply. - A. Encourage adequate fluid intake
- B. Monitor creatinine and urine output
- C. Report new confusion or hallucinations
- D. Hold the antiviral until PCR confirms VZV
- E. Stop the drug and seek help at once if a painful rash with mouth sores develops
Reveal answer & rationale
Q4 Multiple choice His granddaughter, who has never had chickenpox or the vaccine, wants to visit. What should the nurse tell the family? - A. She could catch shingles from him
- B. She could catch chickenpox from the blister fluid, so she should not visit until the lesions crust
- C. There is no risk because shingles is not contagious
- D. She can visit if she wears gloves
Reveal answer & rationale
Q5 Select all that apply Three months later he still has burning pain and pain from clothing touching the old rash area. Which statements are accurate? Select all that apply. - A. This fits postherpetic neuralgia
- B. Gabapentin or pregabalin are first-line systemic options
- C. A lidocaine patch is suitable for older adults because of minimal systemic effects
- D. Opioids are the first-line treatment
- E. He can never receive Shingrix because he has already had shingles
Reveal answer & rationale
Common questions
What causes herpes zoster (shingles) & postherpetic neuralgia?
Can you catch shingles from someone who has it?
How soon should antivirals start?
What is postherpetic neuralgia?
Who should get Shingrix?
Why is shingles near the eye an emergency?
Sources
- Herpes Zoster — StatPearls — StatPearls (NCBI Bookshelf)
- Postherpetic Neuralgia — StatPearls — StatPearls (NCBI Bookshelf)
- Herpes Zoster Ophthalmicus — StatPearls — StatPearls (NCBI Bookshelf)
- Clinical Overview of Shingles (Herpes Zoster) — CDC — Centers for Disease Control and Prevention
- Clinical Features of Shingles (Herpes Zoster) — CDC — Centers for Disease Control and Prevention
- Shingles Vaccine Recommendations — CDC — Centers for Disease Control and Prevention
- Isolation Precautions, Appendix A: Type and Duration of Precautions — CDC/HICPAC — Centers for Disease Control and Prevention
- Shingles — National Institute on Aging — NIH National Institute on Aging
- VALTREX (valacyclovir) — FDA label — U.S. FDA / NLM DailyMed
- SHINGRIX (Zoster Vaccine Recombinant, Adjuvanted) — FDA label — U.S. FDA / NLM DailyMed
Reviewed by Hae Suk Lee, RN
Educational summary for nursing students. Scenarios are fictional teaching cases. Always verify against current guidelines and your institution's protocols before acting in practice. Not medical advice.