Are You Confident of the Diagnosis?
Brachioradial pruritus (BRP) is a form of chronic localized neuropathic itch typically affecting the dorsolateral aspect of the forearms.
What you should be alert for in the historyItch is typically localized to the skin on the dorsolateral forearms overlying the brachioradialis muscles and can extend to the upper arms and shoulders proximally and the wrist distally.
Itch is often intense and associated with paresthetic sensations of burning, prickling, and/or tingling. Itch may be worse with exposure to ultraviolet light, warmth, or wind; it may be worse at night. Many patients find ice packs to be the only way of obtaining symptomatic relief. This has been known as the ‘ice pack sign’.
Although BRP is defined as an itch limited to the upper aspect of arms and forearms, some patients had itching of the lower extremities as well. On the other hand, a number of patients who experienced generalized itch appeared to have their itch triggered by BRP.
Characteristic findings on physical examination
Itch typically affects the cutaneous distribution of the posterior cutaneous nerve of the forearm, a branch of the radial nerve (Figure 1), and associated abnormal sensations to pinprick and temperature may be present in this area. The area affected has also been frequently reported to follow a C5-C8 dermatomal pattern, most commonly involving C5 and C6.
Primary skin lesions are absent. Secondary lesions comprising excoriations, lichenification, and prurigo nodules may be present.
Expected results of diagnostic studies
Routine cervical spine X-rays are advisable to check for structural lesions. Cervical magnetic resonance imaging should be performed if the onset is recent or neurologic deficits are present. The region around the C5 and C6 nerve roots, in particular, should be analyzed.
Biopsy of skin is not usually required, but histologic findings include features of sun damage (atrophy and elastosis) and reduced numbers of nerve fibers in the epidermis and dermis.
Neurotic excoriations: Unlike BRP, itch and excoriations are not localized to the arms.
Post-herpetic neuralgia causing itch: Preceding pain and rash are present. Notable exception is herpes zoster sine herpete, in which no rash is observed. Itch is unilateral (BRP is usually bilateral).
Porphyria cutanea tarda: Involves the dorsum of the hands in addition to the forearms. Skin changes may not be present initially.
Who is at Risk for Developing this Disease?
White Caucasians (Fitzpatrick skin types I-III) appear to be affected more often than darker-skinned individuals. Age of onset is typically during the 40s to 60s. Certain occupations may be susceptible, including tennis players and workers performing repetitive vibratory work.
What is the Cause of the Disease?
BRP is due to neuronal damage. BRP has been believed to result from cutaneous nerve damage from chronic sunlight exposure. Damage at the cervical spinal level has also been implicated as the cause, and associated structural lesions include disc herniation, vertebral degenerative changes, neoplasms, syringomyelia, traumatic spinal lesions, cervical rib, hypertrophic C7 transverse process, and fibrous bands. It is likely that the etiology of BRP is not uniform and both of the above factors contribute to varying degrees in different patients.
Systemic Implications and Complications
In cases that are secondary to cervical lesions, progressive neuronal deficits will occur if enlarging lesions (such as neoplasms and syringomyelia) are not detected.
Exacerbation of symptoms at night is associated with insomnia. Together with the intense and chronic nature of the symptoms, mood disorders (depression and anxiety) may develop.
Treatment is challenging.
Most patients find relief with application of ice packs.
Topical menthol, especially for patients getting relief from ice packs.
Topical anesthetics (e.g. lidocaine or eutectic mixture of anesthesia) may be used in addition.
Topical capsaicin cream (0.025% to 8%) has been used with variable response.
Topical amitriptyline hydrochloride 1%, in combination with ketamine hydrochloride 0.5%, has been described to be effective in a patient.
Numerous drugs have been used but response varies.
Gabapentin (900-3600 mg/day)
Pregabalin (150-300 mg/day)
Lamotrigine (200 mg/day)
Amitriptyline (25-150 mg/day)
Surgery is rarely performed but may be indicated if BRP is due to cervical lesions compressing on nerves, such as disc herniation, neoplasms, cervical rib, or fibrous bands.
Other forms of treatment reported include acupuncture, cutaneous field stimulation, physical therapy, particularly for patients with cervical spinal disease.
Optimal Therapeutic Approach for this Disease
The management approach to BRP is depicted in Figure 2. We use gabapentin and pregabalin as the first-line medications as we find them to be the most efficacious and associated with the least side effects.
Many patients experience exacerbation of symptoms during summer, and sun protection is particularly useful for these patients.
Most cases are chronic with a relapsing and remitting course.
Unusual Clinical Scenarios to Consider in Patient Management
If symptoms of paresthesia are progressive or if the sensation of itch evolves into numbness, magnetic resonance imaging should be performed early to exclude an expanding lesion, such as a neoplasm or syringomyelia.
Tumors previously reported to have caused BRP include ependymoma and cavernous hemangioma.
What is the Evidence?
Bernhard, JD, Bordeaux, JS. “Medical pearl: the ice-pack sign in brachioradial pruritus”. J Am Acad Dermatol. vol. 52. 2005. pp. 1073(This sign was noted to be nearly pathognomonic for BRP.)
Veien, N.K., Laurberg, G.. “Brachioradial pruritus: a follow-up of 76 patients”. Acta Derm Venereol. vol. 91. 2011. pp. 183-5. (Although BRP is defined as an itch limited to the upper aspect of arms and forearms, some patients had itching of the lower extremities as well.)
Kwatra, SG, Stander, S, Bernhard, JD, Weisshaar, E, Yosipovitch, G. “Brachioradial pruritus: a trigger for generalization of itch”. J Am Acad Dermatol.. vol. 68. 2013. pp. 870-3. (On the other hand, a number of patients who experienced generalized itch appeared to have their itch triggered by BRP.)
Fisher, DA. “Brachioradial pruritus wanted: a sure cause (and cure) for brachioradial pruritus”. Int J Dermatol. vol. 36. 1997. pp. 817-8. (Along with itch, altered sensation to pinprick and temperature may be observed in the distribution of the posterior cutaneous nerve of the forearm in BRP.)
Walcyk, PJ, Elpern, DJ. “Brachioradial pruritus: a tropical dermopathy”. Br J Dermatol. vol. 115. 1986. pp. 177-80. (White Caucasians appear to be affected more often than darker-skinned individuals.)
Binder, A, Fölster-Holst, R, Sahan, G, Koroschetz, J, Stengel, M, Mehdorn, HM. “A case of neuropathic brachioradial pruritus caused by cervical disc herniation”. Nat Clin Pract Neurol. vol. 4. 2008. pp. 338-42. (This is one of the cases demonstrating damage at the cervical level as the etiology. Surgery and medications resulted in recovery.)
Veien, NK, Laurberg, G. “Brachioradial pruritus: a follow-up of 76 patients”. Acta Derm Venereol. vol. 91. 2011. pp. 183-5. (In patients having exacerbation of symptoms during summer, sun protection resulted in significantly higher rates of clearance and improvement compared with those who did not adopt sun protection.)
Zeidler, C, Lüling, H, Dieckhöfer, A, Osada, N, Schedel, F, Steinke, S. “Capsaicin 8% cutaneous patch: a promising treatment for brachioradial pruritus?”. Br J Dermatol. vol. 172. 2015. pp. 1669-71. (Topical capsaicin cream (0.025% to 8%) has been used with variable response.)
Poterucha, TJ, Murphy, SL, Davis, MD, Sandroni, P, Rho, RH, Warndahl, RA, Weiss, WT. “Topical amitriptyline-ketamine for the treatment of brachioradial pruritus”. JAMA Dermatol.. vol. 149. 2013. pp. 148-50. (Topical amitriptyline hydrochloride 1%, in combination with ketamine hydrochloride 0.5%, has been described to be effective in a patient.)
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