Abstract
Following reactivation of a latent ganglionic varicella zoster virus and skin eruption in the corresponding dermatome(s) ∼20% of patients develop chronic postherpetic neuralgia. A subset of these patients develop severe and often intractable chronic postherpetic itch in the affected area. However, this is rarely studied and little is known about its epidemiology, pathogenesis, and management. In this case study we followed a patient with moderate to severe chronic postherpetic itch characterized by pure itch sensation, using standardized quantitative sensory testing and observed a profound loss-of-function for C-fibers, Aδ-fibers, and Aβ-fibers within the affected area. The testing was conducted before, during, and after 8% topical capsaicin treatments applied in 4 cycles (3 months apart) over the course of ∼1 year. During this period the hypoesthesia gradually normalized, but heat hypoalgesia remained unchanged. The 8% topical capsaicin had a good and long lasting antipruritic effect eventually resulting in complete resolution of the itch in parallel with partial recovery of initial hypoesthesia, particularly for warmth and cold detection, likely unrelated to the treatments.
Highlights
Chronic postherpetic itch (PHI) is a marginally studied sequela to shingles
The patient consented to the 8% topical capsaicin treatment and the sensory testing as well as to the anonymized data being used for a case report
Achieving satisfactory relief in patients suffering from neuropathic itch such as in PHI is a clinical challenge[1,4]
Summary
Chronic postherpetic itch (PHI) is a marginally studied sequela to shingles. After reactivation of a latent ganglionic varicella zoster virus and skin eruption in the dermatome(s) innervated by a corresponding sensory ganglion, ∼20% of patients develop postherpetic neuralgia with advanced age as the major risk factor[1]. We tested a PHI patient undergoing four 8% topical capsaicin treatment over a year with standardized quantitative sensory testing and showed, before treatment, a notable loss-of-function for C-fibers, Aδ-fibers, and Aβ-fibers in the affected area. The patient consented to the 8% topical capsaicin treatment and the sensory testing as well as to the anonymized data being used for a case report.
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