Brachioradial pruritus (BRP) is a neuropathic condition typically characterized by localized dysesthesia of the dorsolateral arms.1 This dysesthesia has been described as a persistent painful itching, burning, tingling, or stinging sensation2-4 and has a median duration of expression of 24 months.5,6 The condition may be unilateral or bilateral in nature but tends to have a predilection for a bilateral distribution along the C5 to C6 dermatomes.1,7,8 There are no primary skin lesions associated with BRP; however, excoriations, prurigo nodules, and lichenification may arise secondary to scratching of the irritated skin.1,4,5,9 Brachioradial pruritus tends to have a predilection for adult females (3:1 ratio) with lighter skin. The mean age at diagnosis is 59 years, but cases have been reported in patients aged 12 to 84 years.1,5 The diagnosis of BRP is based on clinical signs and symptoms, though the ice-pack sign tends to be pathognomonic for the diagnosis.10,11 Although there is no clear evidence on the exact cause of BRP, there are 2 prevalent theories: cervical radiculopathy secondary to cervical spine pathology and/or excessive exposure to UV radiation (UVR) in the summer months.3-5,12 Brachioradial pruritus remains poorly described in the literature, and even its origin is under debate. As such, the clinician may have difficulty deciding on the best course of management. The goal of this article is to identify and discuss known treatment options for BRP (Table).
Etiology
Cervical Spine Pathology—A correlation appears to exist between BRP and cervical spine changes seen on plain film radiographs at the levels of C3 to C7, with increased incidence at the C5 to C6 levels. These plain film radiographs typically show degenerative joint disease and neural foraminal stenosis at levels that correlate to the dermatomal distribution of BRP.1,7,10,12-14 In addition to plain film radiography, some studies have utilized magnetic resonance imaging to view the cervical spine and have documented evidence of intervertebral disc protrusion/bulging, central canal stenosis, neuroforaminal stenosis, and spondylosis at the affected regions.5,15-17 Moreover, supporting the theory that the cervical spine is responsible for the emergence of BRP, Marziniak et al17 investigated 41 patients with BRP utilizing magnetic resonance tomography to find that 33 patients (80.5%) had changes in nerve compression, and 8 patients (19.5%) had degenerative changes. In addition to these findings, they found that there was a significant correlation (P<.01) between the dermatomal expression of BRP and the location of cervical anatomical changes.17 Further validating the relationship between cervical spine pathology and BRP is a case study of a patient who saw rapid and complete resolution of the pruritus following spinal decompression surgery.10 Another case study described an intramedullary tumor found in a patient with BRP that was diagnosed as an ependymoma after magnetic resonance imaging revealed an intramedullary lesion within the spinal cord between C4 and C7. The location of the tumor and dermatomal pattern of the neuropathic itch pointed to a possible association between nerve compression and BRP.14 Electromyography studies performed on individuals with BRP have shown an increase in polyphasic units, decreased motor units, and/or denervation changes along the C5/C6 or C6 nerve roots, which provides additional support for the theory of cervical spine pathology as a causative factor for BRP.16
UVR Exposure—Another etiologic theory for BRP is that UVR exposure may be responsible for the genesis of pruritus. Previously known as solar pruritus, BRP was deemed a clinical condition, as there was increased prevalence in patients living in warmer climates, such as Florida.9 Wallengren and Dahlbäck18 reported that sun exposure is a notable factor in the onset of BRP, as they saw an increase in symptoms during the late summer and a decrease in symptoms over the winter months. To further support the theory that UVR is linked to BRP, several studies have shown that the utilization of sun protection is linked to a reduction of symptoms, specifically in patients who showed seasonal variations of their symptoms.9,12,19 Additionally, a study by Mirzoyev and Davis5 retrospectively reviewed 111 patients diagnosed with BRP. Of these patients, 84 (75.7%) presented with bilateral symptoms, and 54 (48.6%) reported prolonged sun exposure. Both of these findings demonstrate correlation between UVR and BRP.5 Interestingly, UV light exposure is known to release β-endorphin in the skin and may theoretically provide an area of exploration between UVR and cervical spine theories.
Conservative Treatment
Chiropractic Manipulation—Because one etiologic theory includes disease of the cervical spine, there is evidence that targeting this region with treatment is beneficial.7 Two case reports found in the literature noted that cervical spine manipulation and cervical traction yielded positive results.20,21 It has been established that pain generated by disc lesions can be the result of local nociceptive fiber activation, direct mechanical compression of the nerve roots, or inflammatory mediators.22 There are several postulated models describing the hypoalgesic effects of spinal manipulation, which contains both biomechanical and neurophysiological mechanisms. Biomechanical changes theorized to elicit analgesia include restoration of faulty biomechanical movement patterns, breaking up of periarticular adhesions, and reflexogenic muscle inhibition of hypertonic musculature. Hypothesized neurophysiological effects of joint manipulation include an increase in afferent information overwhelming the nociceptive input, reduction of temporal summation, and autonomic activation leading to non–opioid-induced hypoalgesia.23 Cervical traction is another plausible treatment for BRP, wherein the physiological effects of traction allow for a separation of vertebral bodies and expansion of the intervertebral foramen circumference, thus decreasing compression of the nerve roots.24
Acupuncture—Neurogenic pruritus, including BRP, is a group of conditions that have been treated using acupuncture. Acupuncture treatment consists of intramuscular needle stimulation and has been found to alleviate itching in patients with neurogenic pruritus. In 1 retrospective case series, acupuncture was used to treat 16 patients who were identified as having segmental pruritus. Acupuncture targeted the spasmed paravertebral muscles of the affected dermatomal levels as well as other regions of the body, and it was found that 12 patients (75%) experienced full resolution of symptoms. However, relapse did occur in 6 patients (37%) within 1 to 12 months following treatment.25 Multiple theories exist as to why acupuncture may help. One is that it relieves muscle spasms, which in turn relieves neural irritation of the spinal nerves as they traverse the respective paraspinal musculature. Another is that acupuncture decreases nociception by stimulating release of opioid peptides in the dorsal horn.26 A third proposed theory is that acupuncture acts on the afferent nerve fibers responsible for transmitting pain—Aδ and C fibers—activating these afferent nerves to produce an analgesic effect.27
Physiotherapy—The literature suggests that possible first-line therapies for neurogenic pruritus, including BRP and notalgia paresthetica, consist of noninvasive nondermatologic treatments that target cervical spine disease. Notalgia paresthetica and BRP have similar proposed mechanisms of nerve impingement; therefore, they often are grouped together when discussing proposed manual treatment options. Physiotherapy treatment includes cervical muscle strengthening, increased range of motion, application of cervical soft collars, massage, transcutaneous electronic nerve stimulation, and cervical traction.7 A study of 12 patients by Raison-Peyron et al28 in 1999 discussed the use of spinal and paraspinal ultrasound or radiation physiotherapy. Six patients underwent this treatment, and the symptoms subsided in 4 cases.28 Another study by Fleischer et al29 in 2011 discussed improvement in 2 patients with notalgia paresthetica by exercise involving active range of motion and strengthening.
Photoprotection—Avoidance of UVR exposure has been beneficial to some patients to reduce symptoms. Use of sunscreen and long-sleeved UV-protective clothing during outdoor activities or the warmer summer months may be beneficial.1