Undifferentiated Pruritus Associated with Increased Risk of Hematologic Cancer

Although pruritus is common in patients with hematologic cancers, it is unknown whether patients with undifferentiated pruritus have a higher risk of developing hematologic cancer. Furthermore, it is unclear whether serum lactate dehydrogenase (LDH) level, commonly ordered for cancer workup, has diagnostic utility in patients with pruritus. A study was conducted to assess the risk of hematologic cancer and the diagnostic utility of LDH levels in patients with undifferentiated pruritus.

This retrospective population-level cohort analysis was conducted using the TriNetX Research Network, a global health records database encompassing more than 69 million patients, from 2002 to 2020. The study included 327 502 eligible patients diagnosed with unspecified pruritus, excluding those with existing chronic pruritic dermatoses or systemic diseases are known to cause pruritus, and 327 502 matched controls.

Results:

After matching, the pruritus and control cohorts each had 327 502 patients (68.1% female patients; 0.4% American Indian or Alaska Native patients; 3.5% Asian patients; 22.2% Black patients; 0.1% Native Hawaiian or Pacific Islander patients; 59.3% White patients; mean [SD] age, 42.2 [22] years). Patients with pruritus had increased 1-year risk of Hodgkin lymphoma (RR, 4.42; 95% CI, 2.83-6.88), myeloid leukemia (RR, 2.56; 95% CI, 1.79-3.67), multiple myeloma (RR, 2.38; 95% CI, 1.66-3.41), non-Hodgkin lymphoma (RR, 2.35; 95% CI, 1.96-2.82), monoclonal gammopathy (RR, 1.90; 95% CI, 1.55-2.32), myelodysplastic syndrome (RR, 1.74; 95% CI, 1.14-2.64), and lymphocytic leukemia (RR, 1.47; 95% CI, 1.07-2.02). After 12 months, the cancer risk was comparable with that of controls. Patients with pruritus had increased LDH levels, which were not associated with increased hematologic cancer risk.

In this cohort study, the RR of hematologic cancer in patients with undifferentiated pruritus was highest in the first 12 months, and LDH level had limited diagnostic utility in these patients. Clinicians should consider a thorough review of symptoms and assessment of cancer risk factors when deciding on workup for patients presenting with undifferentiated pruritus.

Reference:

Risk of Hematologic Cancer in Patients with Undifferentiated Pruritus by Junwen Deng et al. published in the JAMA Dermatology.

doi:10.1001/jamadermatol.2022.1562

Keywords:

Risk, Hematologic Cancer, Patients, Undifferentiated, Pruritus, Junwen Deng, Varsha Parthasarathy, Waleed Adawi, Zachary Bordeaux, Nishadh Sutaria, Abhishek Gami, BS1; Matthew Taylor, Kevin K. Lee, Melika Marani, Isabelle Brown, Anusha Kambala, BS1; Hannah L. Cornman, Ali Alajmi, Thomas Pritchard, Olusola O. Oladipo, Yevgeniy R. Semenov, MD2; Shawn G. Kwatra, JAMA Dermatol