Living with
Post-Herpetic Neuralgia (pain from shingles)
What is post-herpetic neuralgia?
Post-herpetic neuralgia is the most common and a very painful complication of shingles. It affects nerve fibres and is characterised by a burning pain that lasts long after the shingles rash has disappeared. The term ‘neuralgia’ is used to show that the pain is caused by damaged, inflamed, or irritated nerves.
Shingles, or herpes zoster, is a localised (limited to a specific area), painful skin rash characterised by blisters. It is caused by reactivation (or reawakening) of the chickenpox (varicella-zoster) virus.
How do you know you have post-herpetic neuralgia?
Post-herpetic neuralgia follows an episode of shingles. Its signs and symptoms are usually limited to the area of skin where the shingles rash first appeared. It is defined as persistence or recurrence of pain, more than one to three months after the onset of herpes zoster. The pain may be intermittent (comes and goes) or continuous.
The following characteristics describe the typical pain from post-herpetic neuralgia:
• A burning, sharp and jabbing, or deep and aching pain that may last three months or longer after the shingles rash has disappeared.
• Sensitivity to light touch so that even the touch of clothing on the affected skin may be unbearable (a phenomenon called allodynia).
• Itching and numbness, although this is less common.
People with post-herpetic neuralgia may develop other complications depending on how long the pain lasts and how severe it is. Common complications from chronic pain include:
• Depression
• Fatigue
• Insomnia (or difficulty sleeping)
• Loss of appetite
• Struggling to concentrate
Although it cannot be seen from the outside, post-herpetic neuralgia represents persistent damage to sensory nerves, and therefore the pain not only outlasts the rash, but may persist for quite some time.
When to see a doctor
It is important to see a doctor at the first sign of shingles. Taking antiviral medicines within 72 hours of developing a shingles rash may reduce the risk of developing post-herpetic neuralgia.
What causes shingles?
The same virus that is responsible for chickenpox, the varicella-zoster virus, also causes shingles. This virus is a member of the herpes family, which is also responsible for fever blisters (or cold sores).
Anyone who has had chickenpox (also called varicella) may subsequently develop shingles. Chickenpox is called the primary infection. After the primary infection, the varicella-zoster virus remains dormant in certain nerve cells in the spine for years before it may become reactivated. Reactivation may be brought about by normal aging, but also by suppression of the body’s immune system. This may be due to due human immunodeficiency virus (HIV) infection, cancer, or use of certain medicines such as chemotherapy or corticosteroids. It is not always possible to pinpoint an exact cause for reactivation, but once initiated, the virus migrates down sensory nerves to the skin to cause shingles.
Shingles is uncommon in adolescents and children younger than 15 years. However, the incidence rises sharply with advancing age, and it roughly doubles in each decade past the age of 50. Approximately 20 % of patients with shingles will go on to develop post-herpetic neuralgia.
Risk factors
Risk factors for the development of post-herpetic neuralgia include:
• Older age (above 50 years)
• Facial infection including involvement of the eye nerve
• A severe case of shingles and/or severe pain throughout an episode of shingles
• Other illnesses (such as diabetes)
• Delay in getting antiviral treatment for more than 72 hours after the rash appeared
• Pain that developed before the appearance of the skin rash or pain during the early stage of shingles
• A compromised immune system
How is the diagnosis made?
The diagnosis of shingles and post-herpetic neuralgia is mostly straightforward. Shingles (or herpes zoster) usually starts off with sensitivity to touch (called hyperaesthesia), pins and needles (paraesthesia), burning pain or itching (pruritis) in the affected area. This is called the prodrome as it is present before the appearance of the rash. While the prodrome may last for one to two days, in some instances it may precede the appearance of the skin rash by up to 3 weeks. The skin lesions usually consist of a rash that is made up of flat, discoloured skin lesions along with small, raised bumps. This type of skin rash is called a maculopapular rash, where the macules are the flat areas, and the papules are the raised lesions. These lesions then evolve into small blisters (also called vesicles) upon a red base. The blisters are generally painful and their appearance may be accompanied by flu-like symptoms and anxiety. Pain is the most common symptom for which patients seek medical attention.
What treatment is available for post-herpetic neuralgia?
Unfortunately, there is no cure, but certain medicines can provide relieve from symptoms. Most people will experience improvement over time, as post-herpetic neuralgia is generally a self-limiting disease. Less than 25 % of patients will continue to suffer from pain at 6 months after the initial episode, and fewer than one in 20 patients still experience pain at one year. Having said that, since the pain may be protracted, treatment may well be frustrating for both the patient and doctor and may require the use of multiple modalities.
It goes without saying that treatment is directed at pain control and options for patients who develop post-herpetic neuralgia despite the early use of antiviral medicines include topical capsaicin, local anaesthetic applications, tricyclic antidepressants, and anti-epileptic medicines. In some instances, doctors may recommend the use of transcutaneous electrical nerve stimulation or acupuncture or the injection of botulinum toxin into the affected area.
Capsaicin is an extract from hot chilli peppers that is applied to the affected skin area three to five times daily. It can only be used once the rash has healed and works by interfering with the manner in which nerve endings function. Unfortunately application of capsaicin is associated with a burning sensation which, although it subsides with continued use, may limit its clinical use. Patches containing the local anaesthetic lidocaine is another option for the topical treatment of post-herpetic neuralgia and are considered particularly effective for patients with allodynia. Such plasters may prove useful when the pain interferes with sleeping or daytime activity, but they cannot be worn for more than 12 hours at a time.
While over-the-counter analgesics (such as paracetamol and non-steroidal anti-inflammatory drugs such as ibuprofen, diclofenac, or naproxen) are unfortunately not highly effective in relieving pain from this condition, they are useful to strengthen the effects of narcotic (or opioid) analgesics in patients with severe pain. Narcotic analgesics will usually only be prescribed for patients who do not adequately respond to other treatment options. However, while opioids (or morphine-like analgesics) carry the risk of addiction and dependency, these medicines are safe for the elderly in the context of cardiac, kidney and liver side effects and may well help to assist selected patients who fail to respond to other medications.
Antidepressants may help to relieve pain by inhibiting the re-uptake of the neurotransmitters serotonin and noradrenaline (norepinephrine). These neurotransmitters are chemical substances that relay messages between nerve cells. Amitriptyline and duloxetine are the two main antidepressants prescribed for post-herpetic neuralgia. While amitriptyline is highly effective for this indication, its use is often limited by a variety of side effects (such as dry mouth, blurred vision, constipation, sedation, and abnormal heart rhythms). For these patients, duloxetine will become the preferred option. It is important to remember that full benefit from treatment with these medicines may only become apparent after a few weeks.
Anti-epileptic medicines (also called anticonvulsants), such as pregabalin and gabapentin, are also frequently used to control pain resulting from injuries or damage to nerves (known as neuropathic pain). These two medicines are newer-generation anti-epileptics and are associated with fewer adverse effects compared to older anticonvulsants such as carbamazepine and valproic acid.
Prevention
A vaccine to prevent herpes zoster (shingles) became available in the early 2000’s and has been reported to reduce the incidence of herpes zoster (shingles) by half. If someone who has been vaccinated should develop herpes zoster, the symptoms are usually less severe. Post-herpetic neuralgia is also less likely to occur. New Zealand recommends that all people aged over 60 years consider the zoster vaccine, while the Centres for Disease Control and Prevention (CDC) in the USA recommends the vaccine for adults 50 years and older.
This is a live vaccine and due to the risk of disseminated herpes zoster infection, it is contraindicated in patients who are immunosuppressed.
Living and managing
Living with post-herpetic neuralgia may be very challenging given the potential severity of the pain as well as its duration. Chronic and unpredictable pain may have detrimental consequences for one’s emotional and mental health and depression, anxiety, emotional distress, fear, and sleep disturbances are commonly experienced by those living with post-herpetic neuralgia. It is important to realise that this is part of the disease and that one should seek professional help for any of these symptoms as soon as they negatively impact on one’s quality of life.
Apart from taking prescription medicines, the following may also help to provide relief from the pain and discomfort of post-herpetic neuralgia:
• Wear comfortable clothing.
• Use cold packs wrapped in a towel and press it to the affected area (although it is not recommended to apply ice directly to the skin).
Additional general measures to improve one’s overall health include:
• Eating a healthy diet consisting of fruits, vegetables, whole grains, lean proteins, and health fats (such as olive oil).
• Establishing a regular and healthy sleep pattern by going to bed and rising at the same time, avoiding too many stimuli close to bedtime, avoiding drinking stimulants (such as caffeine) in the evening, etc.
• Developing a positive attitude by focusing on one’s strengths and not weaknesses and by acknowledging that the pain comes from damage to nerves and not from any fault of your own.
• Making time for oneself and engaging in activities that bring you pleasure (such as reading, watching movies, creating art, or writing).
• Maintain social connection with others.
Anyone suffering from post-herpetic neuralgia may also benefit from engaging in regular exercise fit for one’s age. Remaining in bed for prolonged periods can cause one to stiffen up, lead to muscle and bone weakness, cause problems with sleeping and may give rise to feelings of depression and loneliness. While regular exercise strengthens muscles, increases energy, and makes daily activities easier to engage in, it is also known to reduces stress levels, which may help to make pain more manageable. A physiotherapist, biokineticist or personal trainer may best advise a program that will fit each individual patient’s needs, preferences, and capabilities.
Conclusion
The importance of seeking medical attention at the first sign or symptom of shingles cannot be stressed enough. As important is to seek medical help when pain from shingles continues and to also report any accompanying symptoms, such as depression, anxiety, trouble sleeping and feelings of self-doubt.
References
1. Mayo Clinic Staff; Postherpetic neuralgia – Symptoms and Causes; Mayo Clinic; 2021; accessed on 23 Sept 2021; available from https://www.mayoclinic.org/diseases-conditions/postherpetic-neuralgia/symptoms-causes/syc-20376588?p=1 [MC]
2. Oakley Prof A; Herpes zoster; DermNet NZ; updated Oct 2015; accessed on 08 Oct 2021; available from https://dermnetnz.org/topics/herpes-zoster [DN]
3. Stankus SJ, Dlugopolski M, Packer D; Management of herpes zoster (shingles) and postherpetic neuralgia; American Family Physician; 15 Apr 2000; 15;61(8):2437-2444 [AFP]
4. National Health Services; Post-herpetic neuralgia – Overview; NHS.UK; 19 Jan 2021; accessed on 23 Sept 2021; available from https://www.nhs.uk/conditions/post-herpetic-neuralgia/ [NHS]
5. National Health Services; Post-herpetic neuralgia – Treatment; NHS.UK; 19 Jan 2021; accessed on 23 Sept 2021; available from https://www.nhs.uk/conditions/post-herpetic-neuralgia/treatment/ [NHST]
6. Sampathkumar P, Drage LA, Martin DP; Herpes zoster (shingles) and postherpetic neuralgia; Mayo Clinic Proceedings; 2009; 84(3): 274-280 [MCP]
7. Richter C; The empowered patient’s guide to postherpetic neuralgia (PHN); Practical Pain Management; updated 22 June 2021; accessed on 08 Oct 2021; available from https://www.practicalpainmanagement.com/patient/conditions/postherpetic-neuralgia/empowered-patients-guide-postherpetic-neuralgia-phn [PPM]
8. National Health Services; Ways to manage chronic pain; NHS.UK; 06 Sep 2021; accessed on 08 Oct 2021; available from https://www.nhs.uk/live-well/healthy-body/ways-to-manage-chronic-pain/ [NHS on chronic pain]
References
1. Mayo Clinic Staff; Postherpetic neuralgia – Symptoms and Causes; Mayo Clinic; 2021; accessed on 23 Sept 2021; available from https://www.mayoclinic.org/diseases-conditions/postherpetic-neuralgia/symptoms-causes/syc-20376588?p=1 [MC]
2. Oakley Prof A; Herpes zoster; DermNet NZ; updated Oct 2015; accessed on 08 Oct 2021; available from https://dermnetnz.org/topics/herpes-zoster [DN]
3. Stankus SJ, Dlugopolski M, Packer D; Management of herpes zoster (shingles) and postherpetic neuralgia; American Family Physician; 15 Apr 2000; 15;61(8):2437-2444 [AFP]
4. National Health Services; Post-herpetic neuralgia – Overview; NHS.UK; 19 Jan 2021; accessed on 23 Sept 2021; available from https://www.nhs.uk/conditions/post-herpetic-neuralgia/ [NHS]
5. National Health Services; Post-herpetic neuralgia – Treatment; NHS.UK; 19 Jan 2021; accessed on 23 Sept 2021; available from https://www.nhs.uk/conditions/post-herpetic-neuralgia/treatment/ [NHST]
6. Sampathkumar P, Drage LA, Martin DP; Herpes zoster (shingles) and postherpetic neuralgia; Mayo Clinic Proceedings; 2009; 84(3): 274-280 [MCP]
7. Richter C; The empowered patient’s guide to postherpetic neuralgia (PHN); Practical Pain Management; updated 22 June 2021; accessed on 08 Oct 2021; available from https://www.practicalpainmanagement.com/patient/conditions/postherpetic-neuralgia/empowered-patients-guide-postherpetic-neuralgia-phn [PPM]
8. National Health Services; Ways to manage chronic pain; NHS.UK; 06 Sep 2021; accessed on 08 Oct 2021; available from https://www.nhs.uk/live-well/healthy-body/ways-to-manage-chronic-pain/ [NHS on chronic pain]