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What is PHN?
Post-herpetic neuralgia (PHN), often referred to as post-shingles pain or after-shingles pain, is significant pain that persists three months or more after the healing of herpes zoster lesions or rash. 21
It manifests as local or peripheral pain with symptoms often described as burning, stabbing, or shooting pain, and also allodynia, and hyperalgesia. The incidence of PHN increases with age. PHN is a debilitating neuropathic pain condition that can last for many years and cause serious physical and social disability. 2,9
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Why is PHN often misdiagnosed?
Many patients live with neuropathic pain conditions such as PHN for a long time before they are correctly diagnosed and receive appropriate treatment. 10,11-13
The symptoms of neuropathic pain may vary, and due to its complex pathophysiology, PHN is often difficult to treat. 2,9 Therefore, without a clear diagnosis, patients may undergo 'trial and error' treatments or endure a step-wise treatment approach over months or even years. 14,15 The pain associated with PHN may be intermittent and the patient may not be aware that pain can occur after the shingles rash has healed. An accurate evaluation of pain therefore has a critical role to play in the identification and treatment of PHN.
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How can PHN be diagnosed?
PHN presents differently from patient to patient and there are a number of elements to an accurate diagnosis.
Firstly, the analysis of patient history has an important role to play. In particular, establishing if there has been an episode of shingles recently, and if so, where was this located?
In addition, gaining an accurate description from the patient of the nature of the pain can also prove useful. The pain associated with PHN is often described as 'shooting', 'stabbing' or 'burning'. 2,9
A physical examination and tests for positive or negative sensory signs, allodynia, and hyperalgesia, can be carried out. These can include Q-tip or pinprick tests, hot and cold stimulus, vibration or pressure.
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How can asking questions aid diagnosis?
Different sensory symptoms and types of pain may exist in PHN and these can vary in respect of location, intensity, duration and quality. 16
Therefore, asking the patient about their pain can provide useful indicators to aid diagnosis. For example, the presence of post herpes zoster pain can be assessed by asking, "Do you have any pain in the area where you had your shingles rash?" 16
Such assessments can be supplemented by discussion of pain intensity. There are a number of formalized scales that can be used to describe and measure the intensity of pain, for instance where 0 represents ‘no pain’, through to 10 which represents ‘worst pain imaginable’. Patients can then be asked to rate their pain with a number that best equates to the pain they have experienced over the last 24 hours 16
Asking your patient to describe the type of pain they have been experiencing can also prove useful, words such as ‘shooting’, ‘stabbing’ or ‘burning’ may indicate PHN2
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What treatment options are available?
Pharmacological treatment options for PHN include systemic and topical therapy.
Systemic therapies include anticonvulsants, tricyclic antidepressants (TCAs), serotonin noradrenaline reuptake inhibitors (SNRIs) and opioids which are associated with a number of systemic side effects. 15,17,18,19
With these treatment options, physicians and patients often struggle to find a balance between efficacious dosing and dose-limiting side effects.
Versatis® is a topical treatment which offers proven efficacy 2,3,4, superior tolerability 1,3,+ with a low rate of systemic side effects and is easy for patients to use 1,7 - leading to high levels of patient satisfaction and quality of life improvements. 3,4
(+Compared to pregabalin)
