Erythema nodosum in association with newly diagnosed hairy cell leukemia and group C streptococcus infection

Erythema nodosum as sign of primary tuberculosis

Erythema nodosum is a panniculitis associated with numerous diseases such as infections, inflammatory diseases, tuberculosis or can be idiopathic. We here report a case of a woman with erythema nodosum and reactive arthritis who was subsequently diagnosed with tuberculosis. A high level of suspicion and a thorough clinical and laboratory investigation of the patient presenting with erythema nodosum is required, in order to detect a possible systemic underlying condition.

Autoimmune conditions and hairy cell leukemia: an exploratory case-control study

Background

Case reports suggest that hairy cell leukemia (HCL) may be associated with autoimmune conditions, however no systematic investigations in this area have been undertaken.

Methods

Using the United States Surveillance, Epidemiology, and End Results Medicare linked database, we conducted an exploratory study comparing autoimmune conditions in 418 HCL cases (aged ≥65 years) and 160,086 controls.

Results

Overall, the proportion with autoimmune conditions was similar between HCL cases and controls (n = 79 (18.9%) and n = 29,284 (18.3%), respectively). Before diagnosis/selection, there was no overall difference in the prevalence of autoimmune conditions in HCL cases (n = 37, 8.9%) compared with controls (n = 14,085, 8.8%), p = 0.969. However, compared with controls, HCL cases more frequently had sarcoidosis (OR 9.6, 95%CI 2.4-39.5), Sjögren syndrome (OR 6.1, 95%CI 2.0-19.3) and erythema nodosum (OR 37, 95%CI 4.9-284) before diagnosis. Autoimmune conditions were also more common in HCL cases than controls around the time of diagnosis/selection (p < 0.001) but not subsequently.

Conclusions

The findings do not support an overall relationship between autoimmune conditions and HCL, although the association with some autoimmune conditions prior to HCL diagnosis may warrant further investigation. Our findings also suggest that autoimmune conditions in HCL patients may be detected around the time of diagnosis.