June 15, 2007 • www.familypracticenews.com Skin Disorders 25 Consider Neurogenic Causes for Unexplained Itch

BY MIRIAM E. TUCKER 10% of the population. For most people, commonly associated with Senior Writer it’s simply an occasional annoying itch. But abnormal pinprick and in a small number of individuals, it mani- temperature sensations. In A MELIA I SLAND, FLA. — Neurogenic fests as a severe, constant pruritus on a contrast to NP, in which sources should be considered in patients patch of skin in one or both of the medi- patients may scratch and who have severe pruritus for which a cuta- al scapular borders that may be accompa- rub to alleviate the itch, neous cause can’t be found, Dr. Jeffrey D. nied by numbness, tingling, formication, patients with BP some- ERNHARD Bernhard said at a symposium sponsored burning, hyperalgesia, and tenderness. times actually gouge their D. B by the Dermatology Foundation. Associated findings also may include forearms attempting to al- In many of these cases, there is a non- hyperesthesia, along with reductions in leviate the sensation, Dr. EFFREY . J R

specific rash that is caused by the patients’ pinprick sensitivity, light-touch sensation, Bernhard noted. D repeated scratching rather than by the dis- two-point discrimination, temperature As with NP, evidence ease itself, which can lead to misdiagnosis. sensitivity, and sweat response. Although suggests that BP also aris- “Patients who scratch a lot can end up NP does not ordinarily produce visible es from nerve compres- with a nonspecific rash that may be eczema- skin changes, there may be hyperpig- sion or damage. In a ret- HOTOS COURTESY tous in nature. Don’t assume there isn’t an mentation over the pruritic area and some- rospective study for which P underlying noncutaneous cause,” said Dr. times a “ragged spot” on a blouse or shirt, Dr. Bernhard was a coin- Patients who have brachioradial pruritus sometimes Bernhard, professor of medicine and phys- both caused by the patients’ persistent vestigator, a chart review gouge their forearms to alleviate the sensation. iology in the division of dermatology at the scratching and/or rubbing. of 22 patients with BP University of Massachusetts, Worcester. The condition is believed to result from seen between 1993 and 2000 showed that ders was seasonal in all but two of the pa- Notalgia paresthetica and brachioradial spinal nerve impingement. In a study of 43 in all 11 for whom cervical spine radiog- tients, occurring more often during August- pruritus are two examples of severe itch- NP patients with 61 lesions, 34 patients had raphy had been performed, the cervical December than during the rest of the year es that arise in the peripheral nervous sys- vertebral pathology—including degenera- spine disease correlated with the location (J. Am. Acad. Dermatol. 2005;52:142-5). tem rather than on the skin. tive changes and herniated nucleus pulpo- of the itching (J. Am. Acad. Dermatol. “The temporal course of brachioradial Localized pruritus of the midback, called sus—on spinal radiography. In 28 of the 34, 2003;48:521-4). pruritus and the [histologic] changes in the notalgia paresthetica (NP), occurs in about the changes were most prominent in the In another study of seven consecutive skin similar to those caused by ultraviolet vertebrae that corresponded to a lesional BP patients, electrophysiologic studies of light indicate that sunlight is an eliciting dermatome (J. Am. Acad. Dermatol. the median, ulnar, and radial nerves yield- factor and that cervical spine disease can be 2005;52:1085-7). ed abnormal responses diagnostic of cer- a predisposing factor,” the authors wrote. The authors speculated that spinal vical radiculopathy in four. One of those Another itchy condition, anogenital pru- pathologies that cannot easily be diagnosed patients had polyneuropathy secondary ritus, also may arise from nerve patholo- radiographically, such as cervical fibrous to diabetes. Six of the seven reported sun- gy. In a study of 18 men and 2 women bands or muscle spasms, also might con- light as a trigger for their itch (J. Am. Acad. (mean age 53 years) with “idiopathic” tribute to NP. They urged physicians who Dermatol. 2003;48:825-8). anogenital pruritus, degenerative changes are treating the neuromuscular problems in Indeed, BP also has been named “solar in the lower spine were found on x-ray in these patients to consider pruritus in the list pruritus” because of this curious sun-trig- 16, and lumbosacral radiculopathy con- of signs and symptoms of spinal disease. gering phenomenon. One recent study at- firmed by nerve conduction studies in 16. Another study of 12 NP cases found tempted to determine whether BP was, in Paravertebral injections of triamcinolone dorsal arthrosis or spinal static disequilib- fact, caused by a nerve compression in the and lidocaine reduced the degree of pru- rium on spinal x-ray in 9 patients. Symp- cervical spine or by prolonged exposure to ritus and sleep disturbance but were less toms improved in four of six patients who sunlight. Skin biopsy specimens collected effective in reducing other symptoms such underwent spinal and paraspinal ultra- from itchy skin of 16 BP patients revealed as burning, tingling, and pain (Am. J. Acad. sound or radiation physiotherapy. Those cutaneous innervation visualized by anti- Dermatol. 2005;52:61-6). authors noted that capsaicin has been re- bodies against protein gene product 9.5 Finally, there are many references to ported to relieve symptoms in some NP (general neuronal marker), by antibodies conditions such as “neurotic excoriation,” patients, but only transiently (J. Eur. Acad. against calcitonin gene-related peptide “psychogenic pruritus,” “senile pruritus,” Dermatol. Venereol. 1999;12:215-21). (marker for thin sensory nerve fibers), and in the literature, all suggesting that the itch NP is an uncomfortable condition, but by antibodies against VR1-receptor (mark- is in the patient’s head. “You have to be brachioradial pruritus (BP) can be excru- er for capsaicin-sensitive nerve fibers). careful about assuming people are crazy ciating. Patients describe BP as a “horren- Compared with controls, the BP patients when they actually may have pathologic Localized pruritus of the midback dous itch” that has a “tingling, prickling, had reductions of 23%-43% in various changes in the nervous system that are occurs in about 10% of the population. sometimes burning sensation.” It also is nerve fibers. Itching of the arms or shoul- making them itch,” Dr. Bernhard said. ■ Genetic Markers Sought for Psoriasis, Comorbidity Links

BY NANCY WALSH hort is expected to advance un- obesity, myocardial infarction, and psoriasis patients, compared with Newfoundland, St. John’s. New York Bureau derstanding of the genetics and asthma in women (Dermatologi- the general population. Of 100 Moreover, psoriasis patients in pathophysiology of complex dis- ca 1986;172:298-304). patients aged 50 years and older this cohort died about 10 years V IENNA — Patients with pso- eases such as psoriasis, said Dr. German studies showed that with mild to moderate psoriasis, earlier than the general popula- riasis are at a higher risk for co- Gulliver, chairman and medical diabetes, obesity, hypertension, 28% had heart disease, whereas tion. The mean age at death in morbidities including arthritis, director of a medical research or- and heart failure were overrepre- 21% of 100 patients with severe men with psoriasis was 68.8 years, heart disease, diabetes, cancer, ganization in St. John’s, Nfld. sented in psoriasis patients (J. Am. psoriasis had heart disease; in the whereas the national average was and hypertension than is the gen- Since the 1960s, it’s been known Acad. Dermatol. 1995;32:982-6). general population aged 30-64 77.4 years. The mean age at death eral population, according to new that psoriasis patients are at risk More recently, studies have years, heart disease rate was 17%. for women with psoriasis was 72.7 data presented by Dr. Wayne P. for concomitant disease, with the suggested a link between psoria- Mortality also reflects the in- years, compared with 82.5 years in Gulliver at the 16th Congress of first associations found to be gout sis and increased rates of meta- creased prevalence of these co- women in the general population. the European Academy of Der- and sarcoidosis. Studies in Sweden bolic syndrome and hyperlipi- morbidities, with 44.4% of the Pharmacokinetic studies are matology and Venereology. during the 1980s found associa- demia—as well as a resulting 169 reported deaths in psoriasis ongoing, with certain genetic The Newfoundland and Labra- tions with excess rates of viral in- increase in cardiovascular risk, patients relating to cardiovascular markers for psoriasis having re- dor Centre for Health Information fections, alcoholism, hyperten- Dr. Gulliver wrote in a poster. disease, compared with 36.1% of cently been identified. If further database contains health records sion, pneumonia, cirrhosis, urti- This observation has now been deaths in the general population analyses can identify genetic link- for more than 3,200 patients with caria, and rheumatoid arthritis in confirmed in the Newfoundland of Newfoundland and Labrador, ages between psoriasis and co- psoriasis from this genetically dis- men and women; with iritis and and Labrador psoriasis population, noted Dr. Gulliver, who is also morbidities, genetic screening tinct founder population. ankylosing spondylitis in men; with heart disease being elevated chairman of the dermatology di- could be used for early recogni- Analysis of data from this co- and with lung cancer, diabetes, in mild to moderate and severe vision, Memorial University of tion, Dr. Gulliver noted. ■