A 68-year-old woman wakes with a burning patch below her left shoulder blade. The skin looks normal, so she assumes a strained muscle. Three days later, a band of blisters wraps around only the left side of her back. That sequence, pain first and rash second, is the classic opening of shingles, the disease clinicians call herpes zoster.
Shingles is not a new infection. It is the return of varicella-zoster virus, the same virus that caused chickenpox, often decades earlier. After chickenpox, the virus retreats into sensory nerve tissue near the spinal cord and brain, where it lies dormant. When immune surveillance weakens with age, with illness, or with certain medicines that suppress immunity, the virus can travel back along a nerve to the skin. The result is a painful, one-sided rash in the strip of skin supplied by that nerve.
Most adults already carry the virus. The lifetime risk of developing shingles is about one in three, and the odds climb sharply after age 50. The Centers for Disease Control and Prevention estimates that roughly one million cases occur in the United States each year. For patients, the practical questions are simpler than the virology: what to recognise, and when to start treatment before the pain settles in.
What Shingles Is and Why It Returns
Varicella-zoster virus, abbreviated VZV, is a herpesvirus. Primary infection causes chickenpox. After that illness resolves, the virus enters nerve cell bodies in the dorsal root ganglia, the clusters of neurons that relay sensation from the skin to the spinal cord. A competent immune system usually keeps VZV in a latent state for decades. Reactivation produces shingles, not a second case of chickenpox.
Age is the strongest driver because cell-mediated immunity against VZV declines over time. People with weakened immune systems are also at higher risk, including those receiving cancer chemotherapy, people living with HIV, organ transplant recipients, and patients taking prolonged courses of corticosteroids or other immunosuppressive drugs. Some patients link a shingles episode to severe stress or physical trauma, but the scientific evidence for stress as an independent trigger is weaker than the evidence for age and immune status.
Shingles itself cannot be passed from one person to another. The fluid inside the blisters does contain VZV, so a person who has never had chickenpox or the chickenpox vaccine can acquire chickenpox from uncovered shingles lesions. Covering the rash reduces that risk. Ordinary, uncomplicated shingles is not transmitted through respiratory droplets.
Pain First, Rash Second: The Signs that Matter
For the 68-year-old patient, the first sign was pain without a rash. That prodromal phase, which often lasts 48 to 72 hours, typically feels like burning, tingling, itching, or electric shock-like pain in one dermatome, the area of skin served by a single spinal or cranial nerve. Some people also develop a headache, general aches, or a low-grade fever. Because the skin may look normal early on, shingles can initially be mistaken for a heart, lung, muscle, or kidney problem depending on where the pain sits.
The rash follows the nerve pathway. It starts as flat red patches that become clusters of small fluid-filled blisters within a day or two. New blisters can appear for three to five days. The fluid then turns cloudy, the blisters become pustules, and crusts form by seven to ten days. Healing usually takes two to four weeks, though scarring and colour changes can last longer. A central feature is that the rash stays almost entirely on one side of the body and does not cross the midline. The chest, face, neck, and scalp are common sites. The Centers for Disease Control and Prevention symptom guide includes photos and descriptions that match this progression.
Symptoms vary by nerve. Thoracic dermatomes account for roughly half to sixty percent of cases. When the ophthalmic branch of the trigeminal nerve is affected, the forehead, eyelid, and tip of the nose can be involved, which signals possible eye disease. Zoster sine herpete is a less common form in which pain occurs without a rash, so the diagnosis is easy to delay.
Complications That Outlast the Rash
The most common complication is postherpetic neuralgia, or PHN, defined as pain persisting for at least 90 days after the rash begins. It is not simply a prolonged ache. Patients describe burning, stabbing, or a sharp sensitivity called allodynia, where light touch or clothing against the skin feels unbearable. PHN affects about 10 to 18 percent of people with shingles overall, but the risk rises steeply with age. That is why early antiviral treatment and vaccination both aim, in part, to reduce the chance of chronic pain.
Herpes zoster ophthalmicus occurs when the first branch of the trigeminal nerve is involved and accounts for about 10 to 25 percent of shingles cases. Without prompt antiviral treatment and an eye examination, the infection can damage the cornea, uvea, or retina, and in some cases threaten sight. Ramsay Hunt syndrome is another cranial nerve form: the virus reactivates at the geniculate ganglion, producing facial weakness, ear pain, and blisters in or around the ear, sometimes with hearing loss and vertigo. The National Health Service shingles guide describes these complications and the urgent symptoms that require an eye or ear specialist.
Other possible problems include bacterial infection of the rash, motor weakness if motor nerves are affected, and rarely meningitis or encephalitis. Some observational studies have reported a modest short-term increase in stroke risk after shingles, although the absolute risk for any one person remains small.
Antiviral Treatment and the 72-Hour Window
Antiviral medicines are the core of early treatment. Three oral drugs are used most widely: valacyclovir, famciclovir, and the older drug acyclovir. Valacyclovir and famciclovir have simpler dosing schedules and better absorption than acyclovir. Standard regimens are typically valacyclovir 1,000 mg three times daily for seven days, famciclovir 500 mg three times daily for seven days, or acyclovir 800 mg five times daily for seven days, a schedule that is effective but less convenient because of its five-times-daily dose. Doses should be adjusted for kidney function, and longer treatment may be needed for severe or complicated disease.
The strongest evidence supports starting treatment within 72 hours of the rash appearing. Trials show that early antiviral therapy shortens the period of new blister formation, speeds crusting and healing, and reduces the severity of acute pain, which is often the most disabling early symptom. Inside that 72-hour window, the drug suppresses viral replication before nerve inflammation becomes difficult to reverse. Starting later is still considered in some situations: ongoing new blisters, severe pain, eye or ear involvement, or a weakened immune system. The expected benefit, however, is smaller once the window has passed.
For a patient who arrives after three days, clinicians weigh the details. An otherwise healthy person with already crusted lesions and mild pain generally does not need antiviral treatment. A person with new blisters, facial or eye involvement, or reduced immunity should usually be treated even if the clock has passed 72 hours. Severe, widespread, or organ-threatening disease may require intravenous acyclovir in hospital.
Pain Relief and What the Research Shows
Antivirals treat the virus, but they do not always prevent postherpetic neuralgia. Acute pain should be managed actively rather than endured. Mild to moderate pain often responds to paracetamol, also called acetaminophen, or to nonsteroidal anti-inflammatory drugs such as ibuprofen. For severe acute pain, a clinician may add a short course of a corticosteroid such as prednisone to the antiviral. The evidence is nuanced here: corticosteroids can reduce acute pain faster, but they have not been shown to reduce the risk of PHN.
Once PHN has set in, treatment shifts to medicines that calm abnormal nerve signalling. First-line options include gabapentin or pregabalin, which reduce neuropathic pain; tricyclic antidepressants such as amitriptyline or nortriptyline; topical lidocaine 5 percent plasters applied directly over the painful area; and capsaicin 8 percent patches for localised PHN in specialist settings. These treatments often require gradual dose increases and can cause dizziness, dry mouth, or fatigue.
Opioids such as tramadol or oxycodone are not first-line treatment for postherpetic neuralgia because of dependence risks and limited evidence for long-term benefit. The weight of research supports early, well-dosed non-opioid neuropathic medicines and topical treatment, with referral to a pain specialist when severe pain persists after two or more first-line options.
Prevention with the Recombinant Zoster Vaccine
Vaccination has changed what prevention means for shingles. The recombinant zoster vaccine, sold as Shingrix, is a non-live vaccine made with a single varicella-zoster virus protein plus an adjuvant that strengthens the immune response. It is given as two injections into the muscle, commonly two to six months apart, and is recommended for adults aged 50 and older, including people who have already had shingles or previously received the older live vaccine, which is no longer available in many countries.
In the ZOE-50 trial published in the New England Journal of Medicine, Shingrix was 97.2 percent effective against shingles in adults aged 50 and older. A related trial in adults aged 70 and older reported efficacy of 91.3 percent, and real-world studies have found effectiveness of around 90 percent or higher in the first years after vaccination. The vaccine also reduces the risk of postherpetic neuralgia, the complication patients most often fear.
Common side effects are short-lived: a sore arm, fatigue, muscle aches, headache, and sometimes mild fever or chills for a day or two. Because Shingrix is not a live vaccine, it cannot cause shingles. Completion of the two-dose schedule matters; protection after one dose is substantially lower than after two. Public health agencies emphasise returning for the second dose even if the first caused side effects.
Cost and access vary by country. In the United States, most private insurance and Medicare Part D plans cover the vaccine, though copays and deductibles can create barriers. In the United Kingdom, the National Health Service offers Shingrix to older adults and some immunocompromised people under a phased programme. The Centers for Disease Control and Prevention maintains a vaccine page for patients with eligibility details. People should check local recommendations because age thresholds and eligibility rules differ, and vaccination should be postponed until any active shingles episode has resolved.
When to Seek Care and What to Ask
Because the 72-hour treatment window is short, people with a new one-sided blistering rash should seek care promptly. That advice becomes urgent in several situations.
- A one-sided rash or pain near the eye, the ear, or the tip of the nose
- Rash that is widespread, bleeding, or showing signs of bacterial infection
- Pain that cannot be controlled with simple analgesia
- Confusion, severe headache, stiff neck, or new visual changes
- Any shingles-like rash in a person with a weakened immune system
For the 68-year-old patient, the burning pain three days before the blisters was the first chance to act. Patients can ask a clinician directly: Is this shingles? Should antiviral treatment start now? Is the eye involved? What can be done for the pain today? A same-day review changes what can be offered, because the best evidence sits inside that early window.
Diagnosis is usually made by looking at the rash and its pattern. Laboratory confirmation with polymerase chain reaction, or PCR, on fluid from a blister can clarify atypical cases, including shingles without a rash. PCR is fast and sensitive, which is why it has become the standard when testing is needed.
While the rash is active, people should keep the area clean and dry, avoid scratching, wear loose clothing, and cover the rash until blisters crust to reduce the risk of exposing a non-immune person to VZV. Cool compresses and calamine lotion may ease itching. Topical antibiotics are not needed unless a bacterial infection develops. Avoiding contact with pregnant people who have never had chickenpox, premature babies, and anyone with a weakened immune system is sensible until the lesions have crusted over.
