Itch

: Pruritus is a well-recognized paraneoplastic phenomenon. Previous studies have examined the association of itch with a variety of malignancies in adults. However, no large study has examined this association in a pediatric population. : A retrospective study was conducted of patients age 18 or less seen at Johns Hopkins Health System between 2012 and 2019. : A pediatric hospital population of 1,042,976 patients was reviewed. Pruritus was observed in 3836 pediatric patients of whom 130 also had cancer. Pediatric patients with pruritus were significantly more likely to have concomitant malignancy compared to pediatric patients without pruritus (OR 12.84; 95% CI 10.73-15.35, < 0.001). Malignancies most strongly associated with pruritus included neoplasms of the blood (OR 14.38; 95% CI 11.30-18.29, < 0.001), bone (OR 29.02, 95% CI 18.28-46.06, < 0.001) and skin (OR 22.76, 95% CI 9.14-56.72, < 0.001. : Pruritus is significantly associated with malignancy in the pediatric hospital population. Clinicians should also be aware of the high burden of itch in pediatric malignancies and the variation in pruritus across malignancies.

Central sensitization induces pain augmentation in chronic pain states. An analogous mechanism is speculated for chronic pruritus. This study compared patients with chronic pruritus (n = 79) of different origins (atopic dermatitis, chronic pruritus on non-lesional skin, chronic prurigo) and healthy controls (HC, n = 54) with regard to itch intensity and qualities of sensory symptoms after selective peripheral nerve fibre activation by electrical stimulation at 5 Hz (surrogate for C-fibre function) and 2,000 Hz (surrogate for Aβ-fibre function) using a Neurometer®. Electrically-induced itch was more intense in patients with chronic pruritus than in HC, but patients with chronic pruritus did not report "itch" more often than HC at 5 Hz. Stimulation at 2,000 Hz induced more pricking and tingling, but less throbbing in patients with chronic pruritus compared with HC. Treatment with cooling compound reduced clinical and experimental itch, but did not alter the distribution of sensory symptoms. These data show hyperknesis in chronic pruritus of various origins, arguing for common central sensitization mechanisms.

Pruritus is a common disease symptom with a variety of etiologies known to reduce patient quality of life. We aimed to characterize the racial and gender differences in the presentation of pruritus for itch-related patient visits both within a single institution and nationally. Cross sectional study of patients ≥ 18 years old seen at Johns Hopkins Health System between 1/1/12 and 1/1/18. Results were compared to data from 2005-2011 from the National Ambulatory Medical Care Survey (NAMCS) and the National Health Ambulatory Medical Care Survey (NHAMCS). Our findings indicate that itch patients at JHHS ( = 18,753) were more likely to be black compared to white patients (37% vs. 19%, < 0.01) when compared to patients without itch-a trend also noted nationally based on data from NAMCS/NHAMCS (26% vs. 21%, = 0.05). Black itch patients are also more likely to be diagnosed with prurigo nodularis (OR 2.37, < 0.0001), lichen planus (OR 1.22, < 0.0001), and atopic dermatitis OR 1.51, < 0.0001). Female itch patients are more likely to be diagnosed with autoimmune (OR 1.66, < 0.0001) and psychiatric comorbidities (OR 1.2-1.8, < 0.0001) than male itch patients. When compared to black itch patients nationally, white itch patients were more likely to visit a dermatologist (29% vs. 18%, = 0.028). Our data can identify associated conditions and demographic differences but are unable to support a causal relationship. Black and female patients are more likely to present with pruritus, a symptom associated with comorbidities such as prurigo nodularis, lichen planus, atopic dermatitis, and psychiatric conditions.