Post-herpetic Neuralgia (Shingles)

Shingles is caused by the chickenpox virus, varicella zoster, which stays dormant in nerve cells for life after a childhood infection and can become active again decades later. When it reactivates it travels along a nerve and causes a painful, blistering rash, usually in a band on one side of the body or face. Post-herpetic neuralgia is nerve pain that carries on in the same area after the rash has healed, and it can be severe enough that clothing or bedsheets hurt.

What shingles and post-herpetic neuralgia are, and what they are not

Shingles is not a new infection caught from someone else. It is the reactivation of a virus you already carry, which is why nearly everyone born before routine varicella immunisation in Canada is a candidate for it. You cannot catch shingles from a person who has shingles, although someone who has never had chickenpox or been immunised against it can catch chickenpox from contact with the fluid in the blisters.

Post-herpetic neuralgia is also not simply a rash that is taking its time. It is nerve pain, defined in the Canadian Immunization Guide as pain lasting more than 90 days from when the rash appeared, and the skin can look completely normal while it continues. Pain that feels out of proportion to how the skin looks is characteristic rather than exaggerated, and it is one reason shingles pain is often underestimated by everyone except the person living with it.

Signs and symptoms

• Burning, tingling, itching or shooting pain in one area of skin, often days before any rash appears
• A rash of small blisters in a band on one side of the body or face
• Pain that feels out of proportion to how the skin looks
• Skin so sensitive that clothing or bedsheets hurt
• Fever, headache and feeling generally unwell
• Pain that continues for months after the rash has healed, which is post-herpetic neuralgia
• Eye pain, redness or blurred vision if the rash involves the face near the eye

Episodes differ widely. Some people have a mild rash and little pain, while others have severe pain that outlasts the rash by months, and the same person can have a different experience if it happens again.

What raises the risk

Some things cannot be changed:

• Having had chickenpox, which nearly everyone born before routine varicella immunisation in Canada has had
• Being aged 50 and older, with the risk of both shingles and lasting nerve pain rising with age
• A weakened immune system from cancer, HIV, transplant or immunosuppressive medicines
• Severe pain and a widespread rash during the shingles episode, which are linked to a higher chance of lasting nerve pain

Others can often be worked on, usually with support from a health care team:

• Delay in starting antiviral treatment, since these medicines are used within the first days of the rash
• Long-term conditions such as diabetes that are not well controlled
• Physical and psychological stress, and poor sleep, which are commonly reported around episodes

How shingles is diagnosed in Canada

Shingles is usually diagnosed by a clinician looking at the rash and its pattern, since a band of blisters on one side of the body that does not cross the midline is distinctive. When the appearance is unclear, fluid from a blister can be swabbed and tested by polymerase chain reaction, or PCR, for varicella zoster virus. Post-herpetic neuralgia is a clinical diagnosis, made when pain persists in the same area beyond the point used to define it, and no scan or blood test confirms it. Anyone with a rash near the eye is assessed by an ophthalmologist.

Treatment and day-to-day management

Clinical research for Post-herpetic Neuralgia (Shingles) is enrolling. See the current studies ↓

Care splits into two phases: the shingles episode itself, where timing matters, and the nerve pain that may follow it, which is managed much like other long-term nerve pain. Depending on how early you are seen, where the rash is and how the pain behaves, a health care team may discuss:

• Antiviral medicines taken by mouth, started within the first days of the rash appearing
• Pain management during the acute episode, including over-the-counter analgesics and, in some cases, prescription options
• Medicines used for nerve pain in post-herpetic neuralgia, including topical agents such as lidocaine or capsaicin, certain anticonvulsants, and certain antidepressants
• Referral to a chronic pain clinic, and nerve block or neuromodulation procedures in some centres
• The recombinant zoster vaccine (Shingrix), authorised in Canada, with publicly funded programmes that differ by province and territory

The Canadian Immunization Guide describes a two-dose series of the recombinant zoster vaccine for adults aged 50 and older, and for adults aged 18 and older with weakened immune systems, with doses given 2 to 6 months apart. Guidance on immunocompromised populations was updated in May 2025. Whether any of this fits your situation depends on your own history, and these are decisions for you and your own clinician rather than anything this page can settle.

When to talk to a doctor

• Call 911 or go to an emergency department if shingles is on the face near the eye or the tip of the nose, or if there is eye pain, vision change, weakness of the face, hearing loss, severe headache, a stiff neck or confusion.
• Seek medical care within 72 hours of a new shingles rash appearing, since antiviral treatment is used early in the episode.
• Contact your clinician if pain continues after the rash has healed, if it disturbs your sleep or daily activities, or if you have a weakened immune system and develop any new painful rash.

Why clinical research matters for post-herpetic neuralgia

Post-herpetic neuralgia remains difficult to treat. Existing nerve pain medicines help only some people, and they often cause drowsiness or dizziness that limits how much can be used in older adults. There is also no reliable way to tell, at the time of the rash, who will go on to have lasting pain. Canada has no national surveillance for shingles either, so the burden is estimated rather than counted. Studies now underway include non-opioid analgesics targeting sodium channels and other pain pathways, topical and injectable formulations, neuromodulation, work on the timing and duration of antiviral treatment, and immunisation in people with weakened immune systems.

Nerve pain is notoriously hard to measure, which is why studies rely on detailed symptom diaries and careful follow-up. Taking part is voluntary, the study is explained to you in full during informed consent, and you can withdraw at any time without affecting the care you get from your own doctor. Joining a study does not mean giving up your current pain treatment, and no one can say in advance whether a study will help you personally.

Learn more from Canadian sources

• Canadian Immunization Guide: herpes zoster (shingles) vaccine
• NACI: updated recommendations on the use of herpes zoster vaccines
• Government of Canada: provincial and territorial immunization information
• Public Health Agency of Canada: Adult National Immunization Coverage Survey