Thoughts on the definition of postherpetic pain: the time criterion adds nothing

In postherpetic neuralgia, as in all types of neuropathic pain, it is generally accepted that outcome can be affected early management with specific analgesics. However, when one looks at the diagnostic criteria appearing in the literature, there is no consensus. Authors use the notion of latency to situate the onset of postherpetic neuralgia within the continuum of herpetic pain. Depending on the Author, this latency period ranges from one to six Months after the skin eruption. This latency is poorly compatible with early intervention and not well-adapted to everyday practice. With the aim of finding ways to improve the management of pain, the Neuropathic Pain Expert Group agreed upon a new definition. Postherpetic neuralgia is pain in the involved site after the skin eruption has healed and which displays the features of neuropathic pain. This definition, which does away with the latency criterion, is based on the identification of one or more clinical features of neuropathic pain in a situation of treatment failure, namely: presence of chronic unsolicited pain (burning, tightness, pressure) and/or paroxysmal pain (tingling, stabbing pain) and/or mechanical hyperalgia/allodynia (to friction or pressure) and/or temperature sensitivity (to heat and/or cold). Such pain occurs in circumscribed neurologic zones in which a sensory deficit can be demonstrated and is usually associated with dysesthesia and/or paresthesia.