Shingles can cause complications ranging from lasting nerve pain to vision loss, hearing damage, and even increased cardiovascular risk. The most common complication by far is persistent pain after the rash heals, but the virus can also affect the eyes, ears, brain, and in rare cases, internal organs. Your risk for most complications rises with age and depends partly on where the rash appears on your body.
Postherpetic Neuralgia: The Most Common Complication
Postherpetic neuralgia (PHN) is pain that lingers for months or years after the shingles rash clears. It’s defined as pain persisting at least three months after the rash first appeared, and it’s the complication most shingles patients worry about for good reason. Between 10% and 20% of shingles patients over age 50 develop it.
The risk climbs steeply with age. In a large UK primary care study, 8% of patients aged 50 to 54 developed PHN, compared to 21% of those aged 80 to 84. The pain takes different forms: a constant burning, sharp intermittent stabs, or pain triggered by light touch on the skin where the rash was. Something as gentle as clothing brushing against the area can be excruciating.
For most people, PHN gradually fades over several months. But in the Shingles Prevention Study, among those who developed PHN, 41% still had pain at six months. About 9% of patients in one long-term study still had pain a full year after their rash resolved, and nearly all of them were over 51. Some cases persist for years.
Eye Complications
When shingles affects the forehead and the area around one eye, a condition called herpes zoster ophthalmicus, the virus can damage structures inside the eye itself. In a review of 86 patients with this form of shingles at the Mayo Clinic, 71% had some type of eye involvement. Corneal disease was the most frequent problem, appearing in 47 patients, followed by inflammation inside the eye (uveitis) in 37.
If the cornea is damaged, you may notice blurred vision, light sensitivity, or a gritty sensation in the affected eye. Uveitis causes redness, pain, and floating spots in your vision. Less commonly, the muscles that move the eye can be affected. These complications typically respond to treatment when caught early, but delayed care raises the risk of lasting vision changes. A key warning sign is shingles blisters appearing on the tip of the nose, which signals that the nerve supplying the eye is involved.
Hearing Loss and Balance Problems
Shingles in or around the ear can trigger a condition called Ramsay Hunt syndrome, which happens when the virus reactivates in the nerve near the ear canal. The hallmark symptoms are a painful rash on or inside one ear, facial paralysis on the same side, and ear pain. You may also notice one corner of your mouth drooping or difficulty closing the eye on the affected side.
Hearing and balance problems are common with this form of shingles. Vestibular disorders, which cause vertigo and unsteadiness, occur in 50% to 80% of Ramsay Hunt cases. Hearing loss tends to be more severe at high frequencies and is more likely in patients who also experience vertigo. In one study, 12 out of 15 patients had measurable hearing loss, and 11 had vestibular symptoms. Some patients also develop ringing in the ears.
Treatment started within three days of symptoms significantly lowers the chance of permanent facial weakness. Without prompt treatment, some people are left with lasting facial paralysis, ongoing ear pain, or hearing changes that don’t fully resolve.
Stroke and Heart Attack Risk
One of the less obvious complications of shingles is its effect on the cardiovascular system. An analysis of more than 200,000 adults found that people who had shingles had a nearly 30% increased risk of experiencing a heart attack or stroke afterward. The virus appears to cause inflammation in blood vessel walls, which can promote clot formation. This elevated risk is not limited to people who had shingles on the face or head; it applies broadly.
Brain and Spinal Cord Inflammation
In rare cases, the varicella-zoster virus can spread to the central nervous system, causing meningitis (inflammation of the membranes around the brain and spinal cord) or encephalitis (inflammation of the brain itself). Symptoms include fever, severe headache, confusion, neck stiffness, nausea, and in some cases seizures. In one case series, fever appeared in about 60% of meningitis patients and over 70% of those with encephalitis, while a third of encephalitis patients experienced acute cognitive changes like confusion or disorientation.
These complications can occur even without a visible rash in some cases, which makes diagnosis challenging. Doctors confirm the infection by testing spinal fluid for the virus’s genetic material. Most patients recover, but the condition requires hospital-based treatment and can occasionally leave lasting neurological effects.
Bacterial Skin Infections
The open blisters of a shingles rash create an entry point for bacteria. The two most common culprits are Staphylococcus aureus and group A streptococcus, both of which normally live on the skin and can invade through broken tissue. Signs that a secondary bacterial infection has developed include increasing redness spreading beyond the rash area, warmth, swelling, and pus or cloudy drainage from the blisters. These infections need antibiotic treatment on top of antiviral therapy.
Disseminated Shingles in Weakened Immune Systems
For people with significantly weakened immune systems, whether from chemotherapy, organ transplant medications, HIV, or other conditions, shingles can spread far beyond its usual single-stripe pattern. Disseminated zoster is defined by 20 or more blisters appearing outside the primary rash area, and it signals that the virus has entered the bloodstream.
When this happens, the virus can reach internal organs. A review of 156 cases found that multiple organs were affected in 46% of disseminated cases. The lungs were involved most often (56% of cases), followed by the liver (44%), heart (16%), kidneys (11%), and pancreas (11%). Lung involvement can cause a severe pneumonia, while liver involvement leads to hepatitis with elevated liver enzymes. Disseminated zoster with organ involvement is a medical emergency with high mortality, particularly when the lungs are affected. This level of spread is extremely rare in people with healthy immune systems.
How Vaccination Reduces These Risks
The recombinant shingles vaccine (Shingrix) is the most effective tool for preventing these complications. Full vaccination with both doses reduces the risk of postherpetic neuralgia by 87%. Protection is strongest in the first two years, with 91% effectiveness in year one and 90% in year two, though it dips to 77% after the second year. Even a single dose provides 69% protection against PHN, but the second dose matters: effectiveness is notably higher after completing the series.
Even among people who develop shingles despite being vaccinated, the risk of progressing to PHN is 47% lower compared to unvaccinated people who get shingles. This suggests the vaccine reduces both the likelihood of shingles and the severity of breakthrough cases. People who were on corticosteroids before vaccination still benefited, though their protection was somewhat lower at 75% compared to 88% in those not taking corticosteroids.