We all know that itching is a part of conditions such as hives, eczema, and psoriasis. We aren’t surprised when skin itches as it’s healing from injuries such as sunburn, trauma, and weed exposures. Sometimes, though, itching can seem to come from nowhere; there has been no contact with allergens, and no new, identifiable skin disorders have developed.
Such unexplained itching can be tolerated if it is short-lived or mild. If it continues with neither relief nor explanation, it can quickly become mentally and physically draining. The itching can significantly impair sleep and concentration, and ineffective treatment becomes demoralizing. Sadly, this is the experience for untold numbers of people who deal with brachioradial pruritus, a disorder characterized by intense itching in the forearms.
Brachioradial Pruritus: Localized Symptoms
Brachioradial pruritus is described in some literature as a sort of neuropathic cutaneous dysesthesia–abnormal sensations in the skin with a neurological origin. It affects the proximal extremities, most particularly the sides and backs of the forearms. Many dermatologists see it as a subset of “neurogenic itch” with a strong association with changes in the cervical spine.
Most patients experience symptoms on both arms, but it isn’t unusual for it to affect only one. It can spread to other parts of the body, usually the upper arms, neck, and shoulders. Patients describe the itching as a “deep” itch that worsens with scratching. This deep itching is frequently accompanied by other sensations, such as tingling, burning, and stinging.
Brachioradial pruritus is an uncommon condition, although there are no sound statistics on its prevalence. It occurs across a wide array of ages, but it most frequently affects fair-skinned women in their forties and fifties–the mean age at diagnosis is 59.
The etiology of the disorder is not clear. While studies have been limited, the evidence suggests that multiple factors are involved in the development of the disease, with a combination of spinal degeneration and excessive sun exposure predominating. Underlying dry skin and underlying atopic dermatitis are potential triggers and associations.
The most widely-accepted hypothesis involves damage to the dermatome responsible for relaying sensations in the skin of the forearms. A dermatome is an area of the skin supplied by sensory neurons that are connected to a single spinal nerve. The human body is equipped with 30 dermatomes, but the ones that connect the nerves in the skin of your forearm to your spine are all found in the cervical (neck) vertebrae–specifically vertebrae b C5 and C8. The dermatomes of the forearm terminate at vertebrae C5 and C6.
While imaging studies are not required to diagnose brachioradial pruritus, spinal abnormalities are often found in patients diagnosed with the disorder. These spinal abnormalities occur most frequently at the dermatomes between vertebrae C5 and C8, and degenerative joint disease (DJD) is the most frequently reported abnormality.
Other spinal abnormalities associated with brachioradial pruritus include herniated disks, osteoarthritis, and foraminal stenosis (the narrowing of the space in the vertebra where the nerves extend from the spine towards the rest of the body).
Surprisingly, most brachioradial patients do not report neck pain when they are evaluated–even when spinal abnormalities are found.
Exposure to ultraviolet radiation (UVR) also appears to contribute to brachioradial pruritus. In one study, 86% of brachioradial patients at a private dermatology clinic either worked outdoors or had outdoor hobbies. Biopsies done on these patients revealed areas of actinic elastosis, abnormal accumulations of the protein elastin, in the dermis.
Actinic elastosis, also called solar elastosis, occurs with cumulative sun exposure. These findings are similar to those of other brachioradial pruritus studies, supporting a link between brachioradial pruritus and sun exposure. The symptoms tend to lessen or completely remit during the winter months–further evidence of the link to sun exposure.
Most patients find that brachioradial pruritus is exacerbated by heat and alleviated by cooler temperatures. Physicians treating the disorder usually note a positive “ice pack sign” for brachioradial pruritus patients; applying an ice pack to the affected area typically relieves symptoms, which return promptly when the ice pack is removed.
In some studies, a reduction of epidermal and dermal nerve fibers in the skin of the brachioradial pruritus patients was noted. Researchers in these studies hypothesize that sun damage causes nociceptors (the nerve endings responsible for transmitting painful stimuli from the skin to the central nervous system) to fire spontaneously, while nerve compression in the cervical spine amplifies those impulses.
A Long Path to Diagnosis
The average brachioradial pruritus patient is diagnosed two or three years after symptoms begin. During this period, patients often find themselves frustrated by inadequate treatments based on incorrect diagnoses. Because the itching is not directly associated with histamine release, antihistamine treatments–prescribed frequently for urticaria–are not always enough in and of themselves to address the deep itch of brachioradial pruritus.
The disorder is often misattributed initially to atopic dermatitis or urticaria; less frequently, physicians might suspect zoster sine herpete (an atypical presentation of shingles without lesions) or skin-picking disorder (excoriation). Brachioradial pruritus itself does not usually cause redness or lesions, but because the itch is so intense, injuries caused by scratching are not unusual. Sufferers are often healing and concealing scabs, crusts, and obvious scratch marks. This scratching can aggravate pre-existing atopic dermatitis.
As we’ve stated before, brachioradial pruritus symptoms tend to abate in the cooler months; this leads some undiagnosed patients to believe that the condition has resolved. The symptoms return with a seasonal change or a trip to warmer climates, starting the entire process again.
Most diagnoses are made by dermatologists. The dermatologist takes an extensive patient history, and they may see if the sensations are relieved with the application of an ice pack. Your Board-certified dermatologist is going to have the best “insight” for why this is not just urticaria or atopic dermatitis.
Options for Topical Treatments
If you have been diagnosed with brachioradial pruritus–or think you could have it–you probably wonder what treatments are available to you. There are both systemic and topical treatments for brachioradial pruritus, and while there is no consensus about the efficacy of these treatments, most patients respond well to at least one.
There are conflicting reports about the efficacy of topical antihistamines. Some patients report that they provide limited relief from itching while the stinging and burning sensations remain. Others report little to no benefit. These treatments have few unwanted side effects, though, and they’re often the first treatment attempted. Consistent moisturizing of dry skin should be part of the first treatments.
Topical application of capsaicin, the compound that gives chili peppers their kick, is another disputed treatment. It may seem counterintuitive, but when absorbed through the skin, fiery capsaicin reduces the amount of a pain transmitter called Substance P in the nerve endings. Some studies report a high level of patient satisfaction with capsaicin treatments; others report that it is relatively ineffective.
There are some drawbacks to capsaicin; it can cause burning at the beginning of treatment, and it can take a few weeks for patients to see results. The relief afforded by capsaicin is temporary, and regular reapplication is necessary.
Topical anesthetics such as 2% - 10% menthol creams, Pramoxine (Sarna® lotion) and lidocaine gels or patches are another option. A newer topical treatment combines a small amount of the anesthetic ketamine with amitriptyline, a tricyclic antidepressant that has long been used orally for neuropathic pain. Compounded topical ketamine is generally well-tolerated and does not have the same risks as oral or intravenous ketamine.
Amitriptyline is thought to work by reducing the amount of noradrenaline and serotonin reabsorbed by nerve cells; these neurotransmitters are part of a stress response, and they are associated with greater sensitivity to painful stimuli. Together, compounded topical amitriptyline and ketamine work on both the nociceptive pain (pain caused by tissue damage) and the neuropathic pain (pain caused by damage to the neurons) involved in brachioradial pruritus.
Side effects of this treatment can include dryness and itching. Some recent studies indicate that gabapentin, an anticonvulsant used to treat epilepsy, is more effective topically than amitriptyline.
SmartLotion® is another option for treating brachioradial pruritus. SmartLotion® was developed by board-certified dermatologist Steve Harlan, MD as a safe, long-term intermittent treatment for his patients with chronic recurring skin disorders. SmartLotion® contains a small amount of hydrocortisone (0.75% USP) that relieves itching without exposing long-term users to the risks associated with higher doses of topical steroids. Dr. Harlan formulated SmartLotion® so that his patients could benefit from a safe and effective treatment regardless of the maintenance schedule they required when supervised by their dermatology provider. SmartLotion® helps with associated inflammation that often occurs from scratching and from other topical treatments. This is good news for people with brachioradial pruritus.
Dr. Harlan usually instructs his brachioradial patients to apply SmartLotion® three or four times daily for two weeks; after that, he has them taper gradually to a single daily application with extra applications allowed for itching spells.SmartLotion® is a safe and effective addition to most prescribed brachioradial pruritus treatments; consult your dermatologist to discuss adding SmartLotion® to your treatment regimen. Like any medication, it should be used under your doctor’s guidance.
Systemic Treatment Options
Not all brachioradial pruritus treatments are topical. Oral antihistamines such as hydroxyzine are frequently prescribed by Dr. Harlan to reduce the amount of histamine released in the skin by scratching. This is especially important for patients who tend to “welt-up” with scratching. He has found that his patients often respond well to non-sedating antihistamine allergy medicines Zyrtec® and Claritin®. He says he often has them take the two concurrently, Cetirizine (Zyrtec®) at night and Loratadine (Claritin®) in the morning.
Both gabapentin and amitriptyline, previously discussed as topical treatments, can be administered orally for treatment of brachioradial pruritus. Both medications can have sedating effects; some patients work around this by taking these medications at night. Like gabapentin, lamotrigine, carbamazepine, and valproate are anticonvulsant medications that are sometimes used to treat brachioradial pruritus. At this point it’s good to have Neurology consulting and following.
Some psychiatric medications can be used off-label to treat brachioradial pruritus symptoms, also. Among these are risperidone, fluoxetine, and chlorpromazine. These can be very important when patients develop a fear or a delusion of “bugs” causing the itch.
Regardless of the treatment options you pursue, relief from brachioradial pruritus symptoms begins with good self-care. This includes avoiding unnecessary sun exposure and other sources of ultraviolet radiation (fingernail polish dryers, UV lights used to cure resin crafts, and tanning beds are all sources of UVR). If you aren’t already using sunscreen daily, now is the time to start. A good sunscreen with an SPF of at least 30 should be applied to all skin that is exposed to sunlight.
Because heat is a common trigger for brachioradial pruritus, patients should minimize their use of saunas, hot tubs, and hot showers. Where possible, avoid heated environments. Applying ice is helpful during pronounced itching spells: Dr. Harlan advises his patients to place either a bag of frozen peas or an ice pack on the affected skin for two minutes at a time. Ice should not be applied directly to the skin.
Maintaining your skin’s moisture is important for brachioradial pruritus patients, especially if they have other disorders that are worsened by scratching. Dr. Harlan insists that his brachioradial pruritus patients moisturize regularly during treatment. CeraVe®, Aveeno®, and Cetaphil® are examples of readily-available moisturizers that he recommends.
While it’s instinctive to scratch at itching skin, scratching worsens brachioradial pruritus symptoms and damages the skin. As it does with eczema patients, scratching sets off an itch-scratch cycle; itching becomes more and more pronounced as patients scratch, which encourages more scratching. Getting ahead of this vicious cycle will help you manage your symptoms more effectively; menthol or pramoxine lotion, ice packs and SmartLotion® can help you weather itching spells without scratching. And don’t let dry skin contribute!
Outlook For Brachioradial Pruritus
Little data exist on the long-term outlook for brachioradial pruritus. Many patients report that their symptoms improve dramatically or resolve completely within weeks of diagnosis and treatment. For others, the symptoms become part of their lives, with recurrences treated as needed–just like any other chronic skin condition.
A few find that their symptoms resist treatment. Very rarely, these patients benefit from surgery to correct spinal abnormalities. Some literature suggests that recalcitrant cases respond well to physical therapy. As with almost all studies done on the disorder, there is no consensus on these findings.
If you have symptoms of brachioradial pruritus, you should see a board-certified dermatologist. If you do not respond to treatment, a referral to a neurologist could be in order. Some studies suggest that brachioradial pruritus sufferers benefit from talk therapy; because the disorder can be so stressful, and because stress is known to increase the skin’s sensitivity to painful stimuli, consultation with a licensed therapist bears consideration.
Communicate honestly with your dermatologists about any concerns you have regarding your treatment, but remember that patience is key. Any treatment, whether it’s topical or systemic, will require time to take full effect.
Brachioradial pruritus is a disorder most of us wouldn’t wish upon our worst enemies; if you suffer from it, you should become your own best friend. Reduce stress levels as much as possible and find outlets that help you manage unavoidable stressors. Protect your skin from UV radiation, and if your skincare regimen is lackluster, upgrade to more effective products. Remember that SmartLotion® is available when your symptoms flare.
Steven Harlan MD
Board Certified Dermatologist
Inventor of SmartLotion®