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What Caused This Refractory Unilateral Pruritic Hyperpigmented Eruption?

What Caused This Refractory Unilateral Pruritic Hyperpigmented Eruption?

Diagnosis: Atypical Spinal Lumbar Paresthetica Associated With L4-S1 Severe Disc Disease in a Young Woman With a Newly Diagnosed Autoimmune Disorder 

Spinal paresthesias, or spinal paresthetica, are neurocutaneous disorders that embody skin-itch-spine syndromes (SISS), including notalgia paresthetica (NP), brachioradial pruritus (BRP), and meralgia paresthetica (MP). DermDx Figure 1These pruritic conditions are heavily underrecognized and underdiagnosed causes of episodic and chronic localized dysesthesias and itching of the midback, upper extremities, and lateral thighs, respectively.1-7While NP and BRP are often described as independent conditions, these two conditions do often occur concurrently or serially in the same individual.1,2 Similarly, the described L4-S1 paresthesias are not uncommon and do frequently occur contiguously or subsequently in the same patients with NP and BRP (HB Skinner, MD, PhD; oral communication, January 2019). 

The term paresthesia describes the burning or prickling sensation usually felt in the hands, arms, legs, or feet, but these sensations can also occur in other parts of the body.8 The sensation, which happens without warning, is usually painless and described as tingling or numbness, skin crawling, or itching. Spinal paresthesias such as NP and BRP may in fact represent the same spectrum of one pathophysiologic neuropathic disorder originating from the cervical spine, whereas the condition described herein originates from the lumbosacral spine.1-7

The fourth through sixth cervical vertebrae as well as the fourth lumbar through first sacral vertebrae are the two most injury- and degenerative disease-prone segments of the human spine. Conversely, the thoracic spine is largely stabilized by ribs and thus much less prone to injury (with the exception of compression fractures). This “weakest link” concept has been postulated by this author and others due to the potential premature evolution of Homo erectus (meaning upright man). Thus, it likely follows that while the erect human position has given humans tremendous advantages, the relative instability of the cervical and lumbar spine has also resulted in significant disease, likely including spinal paresthesias (HB Skinner, MD, PhD; written communication, January 2020).

DermDx Figure 2Treatment 
A timely paradigm shift in the dermatologist’s recognition of the continuum of spinal paresthesias or SISS, including NP, BRP, and MP, as neurocutaneous disorders as well as a substantially redirected treatment approach to these conditions is warranted. The dermatologist’s focus should be placed on eliciting relevant spinal history, including cervical or lumbar muscle spasm, trauma, arthritis, degenerative disk disease, and other spinal neoplasms, and referring for treatment.1,2,6,7,9

Topical therapies for SISS including NP and BRP have been highly inconsistent and nearly entirely unsatisfactory in a majority of patients.1-3,9 Thus, treatment should be aimed at the spine, not the skin. Further, appropriate patient education for nearly all spinal paresthesias requires discussion of potential spinal conditions and clear awareness of the probable association of the localized itching with underlying spinal and musculoskeletal disease. 

Radiographic studies of the spine, including plain film and magnetic resonance imaging (MRI), should be considered in primary evaluation of refractory spinal paresthesias (SISS), including NP, BRP, and MP, more frequently than current standards. 

First-line therapy for spinal paresthesias with associated spinal disc disease should include consideration of potential nondermatologic therapies aimed at the spine.1,2,6,7,9 DermDx Figure 3Such spinal treatments include transcutaneous electrical stimulation (TENS), electrical muscle stimulation (EMS), acupuncture, infrared phototherapy, physical therapy, myofascial massage, muscle strengthening and range of motion enhancing routines, passive continuous motion, alternating heat and ice modalities, gentle spinal traction, mild spinal manipulation, oral nonsteroidal anti-inflammatory medications, and oral and topical muscle relaxants as required for resistant disease.1,2,5-7,9,10

Prognosis and Disease Management 
Similar to prognostication of standard cervical or lumbar musculoskeletal diseases, spinal paresthesia conditions, including NP, BRP, and MP, are generally chronic, controllable conditions with periodic remissions and exacerbations. Collaborative multispecialty evaluation by dermatology, radiology, neurology, pain management, acupuncture, physical therapy, and orthopedic surgery may be indicated for best practices of management of these very common, albeit heavily underdiagnosed, unrecognized, and mistreated, conditions.1,2

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