Background: Chronic pruritus is a debilitating condition associated with a wide range of dermatologic, systemic and psychogenic etiologies. In patients with chronic pruritus that is refractory to conventional therapy, symptoms can significantly decrease quality of life by contributing to anxiety, sleep disturbances, and in many cases depression. Recent studies have demonstrated the effectiveness of mirtazapine in relieving chronic itch that is refractory to standard first-line therapies. Methods: We searched PubMed for English-language articles containing the words (“pruritus” or “itch”) AND “antidepressant” and then conducted a systematic review of the current literature to summarize the efficacy of mirtazapine in treating chronic itch. Results: All studies reported a reduction in itch intensity following the administration of mirtazapine. Conclusion: Collectively, these studies suggest the potential for mirtazapine to relieve chronic itch attributed to dermatological causes and malignancies. As, such mirtazapine may be an option for patients with chronic pruritus that is refractory to typical first-line treatments.

Background: Prurigo nodularis (PN) is an intensely pruritic skin condition of considerable morbidity. However, the pathogenesis of PN and its association with underlying neuropathy is unclear. Objective: We sought to investigate the association between PN and etiologies of peripheral neuropathy. Methods: A cross-sectional analysis of adult patients (≥18-year-old) with PN, AD, and Psoriasis at the Johns Hopkins Health System over a six-year period (January 2013–January 2019) was performed. The strength of association with etiologies of peripheral neuropathy were compared to a control cohort of individuals without PN, as well as those with AD or psoriasis. Results: A total of 1122 patients with PN were compared to 10,390 AD patients, 15,056 patients with psoriasis, and a control cohort of 4,949,017 individuals without PN, with respect to 25 comorbidities associated with peripheral neuropathies. Limitations: Comparisons between peripheral neuropathies and PN represent associations but are not causal relationships. Conclusion: Prurigo nodularis is strongly associated with peripheral neuropathies, suggesting a role for neural dysregulation in pathogenesis.

Background: Mycosis fungoides (MF) is a cutaneous T-cell lymphoma. Previous reports have suggested MF is associated with inflammatory conditions such as psoriasis, increased cardiovascular risk factors as well as secondary neoplasms. Methods: A cross-sectional study of MF patients seen from 2013 to 2019 was performed. Comorbidities were selected based on the 2015 Medicare report highlighting the most common chronic medical illnesses in the United States. Lifetime comorbidity occurrence in patients with MF were compared with that in patients with atopic dermatitis, psoriasis and patients without MF. Additional analyses were performed with patients sub-stratified by race. Results: Compared to control groups, MF was strongly associated with lymphomatoid papulosis and Hodgkin’s disease, but not significantly associated with lung, breast or colon cancer. Interestingly, the association with lymphomatoid papulosis was observed in Caucasians (CI 1062-4338; p < 0.001) and not African Americans (p = 0.9). Patients with MF had a greater association with congestive heart failure, hypertension (HT) and hyperlipidemia (HLD) compared with the general population. However, they were significantly less likely to have HT and HLD when compared with psoriasis patients (HT CI: 0.6–0.9; p < 0.001, and HLD CI: 0.05–0.07; p < 0.001). MF patients were also significantly less likely to have concomitant vitamin D deficiency compared with atopic dermatitis (AD) and psoriasis (p < 0.001). Conclusions: Our results suggest that the association of MF with lymphomatoid papulosis varies by race. Compared to the general population, hypertension and hyperlipidemia were positively associated with MF, however, these were significantly less likely on comparison to psoriasis. Unlike previously described, vitamin D deficiency was found to be significantly less in patients with MF.

Background: Granuloma annulare (GA) is a cutaneous granulomatous disorder of unknown etiology. There are conflicting data on the association between GA and multiple systemic conditions. As a result, we aimed to clarify the reported associations between GA and systemic conditions. Methods: A retrospective, cross-sectional, case-control study was performed in which the medical records of biopsy-confirmed GA patients ≥18 years of age, who presented to the Johns Hopkins Hospital System between 1 January 2009 and 1 June 2019, were reviewed. GA patients were compared to controls matched for age, race, and sex. Results: After adjusting for confounders, GA patients (n = 82) had higher odds of concurrent type II diabetes (odds ratio (OR) = 5.27; 95% confidence interval (CI), 1.73–16.07; p < 0.01), non-migraine headache (OR = 8.70; 95% CI, 1.61–46.88; p = 0.01), and a positive smoking history (OR = 1.93; 95% CI, 1.10–3.38; p = 0.02) compared to controls (n = 164). Among GA patients, women were more likely to have ophthalmic conditions (p = 0.04), and men were more likely to have cardiovascular disease (p < 0.01) and type II diabetes (p = 0.05). No differences in systemic condition associations were observed among GA subtypes. Conclusions: Our results support the reported association between GA and type II diabetes. Furthermore, our findings indicate that GA may be associated with cigarette smoking and non-migraine headache disorders.

Background: 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. Methods: A retrospective study was conducted of patients age 18 or less seen at Johns Hopkins Health System between 2012 and 2019. Results: 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, p < 0.001). Malignancies most strongly associated with pruritus included neoplasms of the blood (OR 14.38; 95% CI 11.30–18.29, p < 0.001), bone (OR 29.02, 95% CI 18.28–46.06, p < 0.001) and skin (OR 22.76, 95% CI 9.14–56.72, p < 0.001. Conclusions: 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.