Similarities between neuropathic pruritus sites and lichen simplex chronicus sites.

BACKGROUND: Localized itch of non-pruritoceptive origin is often neuropathic and may be referred to as neuropathic itch syndrome. OBJECTIVES: To describe the results of nerve conduction studies in patients with anogenital pruritus, brachioradial pruritus and scalp dysesthesia, and compare these sites to typical sites of lichen simplex chronicus (LSC). METHODS: The study summarizes previously published data combined with unpublished data of patients with scalp dysesthesia. Nerve conduction studies included measurements of distal sensory and motor latency, conduction velocity and F-responses. RESULTS: A neuropathy was demonstrated in 29 of 36 patients with anogenital pruritus (80.5%), 8/14 with brachioradial pruritus (57.1%) and 4/9 with scalp dysesthesia (44.4%). The typical sites overlapped with some but not all LSC sites. CONCLUSIONS: A considerable proportion of patients with brachioradial pruritus, anogenital pruritus and scalp dysesthesia have abnormal nerve conduction findings, suggesting a neuropathic origin. The skin sites overlap with some common LSC sites, suggesting that in some cases of LSC a local neuropathy could be a possible cause.

Brachioradial pruritus: a symptom of neuropathy.

BACKGROUND: Brachioradial pruritus (BRP) is a localized pruritus of the dorsolateral aspect of the arm. BRP is an enigmatic condition with a controversial cause; some authors consider BRP to be a photodermatosis whereas other authors attribute BRP to compression of cervical nerve roots. OBJECTIVE: We sought to investigate the presence of neuropathy in patients with BRP. METHODS: We performed electrophysiologic studies of the median, ulnar, and radial nerves in consecutive patients with BRP, including measurement of sensory and motor distal latency, conduction velocity and F responses of the median and ulnar nerves, and sensory distal latency of the radial nerves in both upper limbs. RESULTS: Included in the study were 7 patients, 5 men and 2 women, with an average age of 58.3 years (range: 42-72 years). Of the patients, 4 (57%) had abnormal F responses that were diagnostic for cervical radiculopathy, and 3 of these patients had prolonged distal latencies of the nerves tested, which may be interpreted as sensory motor neuropathy secondary to chronic radiculopathy. The fourth patient had polyneuropathy secondary to diabetes mellitus. CONCLUSION: BRP may be attributed to a neuropathy, such as chronic cervical radiculopathy. The possibility of an underlying neuropathy should be considered in the evaluation and treatment of all patients with BRP.