A 75-YEAR-OLD MAN presented to the dermatology clinic for evaluation of localized, persistent burning pain and discomfort attributed to shingles and postherpetic neuralgia. He had received a diagnosis of shingles on his left upper back about 3 years prior to this presentation.
In the ensuing years, the patient had been evaluated and treated by his primary care physician, a pain management team, and a neurologist. These clinicians treated the symptoms as postherpetic neuralgia, with no consensus explanation for the skin findings. The patient reported that his symptoms were unresponsive to trials of gabapentin 800 mg tid, duloxetine 60 mg PO qd, and acetaminophen 1 to 3 g/d PO. He also had undergone several rounds of acupuncture, thoracic and cervical spine steroid injections, and epidurals, without resolution of symptoms. The patient believed the only treatment that helped was a lidocaine 4% patch, which he had used nearly every day for the previous 3 years.
Physical exam by the dermatologist revealed a lidocaine patch applied to the patient’s left upper back. Upon its removal, skin examination showed a well-demarcated, erythematous, hyperpigmented, lichenified plaque with excoriations and erosions where the patch had been (FIGURE).
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