BI29 Treatment-associated anaemia on Janus kinase inhibitors for atopic dermatitis: a case report, review of the literature and discussion of treatment

Abstract Anaemia is a reported side-effect of Janus kinase (JAK) inhibition. Severe symptomatic anaemia is rare. With the licensing of JAK inhibitors for atopic dermatitis (AD) comes the need for awareness of potential complications and their management. We treated a 74-year-old woman with lifelong AD, refractory to multiple systemic treatments including ciclosporin, methotrexate, mycophenolate mofetil and dupilumab, with upadacitinib 30 mg daily. Her medical history included stable IgA monoclonal gammopathy of unknown significance. Baseline haemoglobin was 11.6 g dL−1, and mean cell volume 101 fL. Her Eczema Area and Severity Index (EASI) fell from 18 to 0. Two months after initiation of upadacitinib, the patient attended a routine haematology appointment. Blood tests revealed a haemoglobin of 8.1 g dL−1 and mean cell volume of 101 fL. Our haematology colleagues recommended holding upadacitinib. When she attended for repeat haemoglobin 1 week later, she presented with dyspnoea, pallor and malaise. Haemoglobin was 7.3 g dL−1. She was referred to the emergency department, where red cell concentrate was transfused. She remained extremely symptomatic. Haematology recommended initiation of darbepoetin alfa at 150 μg weekly. Blood tests were monitored until haemoglobin reached 12 g dL−1. At this point, upadacitinib 15 mg once daily was started. Darbepoetin was stopped 4 weeks later. Haemoglobin has remained stable. After 4 weeks back on upadacitinib, her eczema had cleared. A search of Embase, MEDLINE, PubMed and the Cochrane Database for ‘anaemia’, ‘jak inhib*’, ‘anemia’ and ‘upadacitinib’ yielded 275 results. After screening, 29 remained. Significant anaemia, while a known side-effect of JAK inhibition, has not been reported in the dermatology literature outside clinical trials. The mechanism of anaemia with JAK inhibitors is blockade of erythropoietin signalling by JAK1 [Parmentier JM, Voss J, Graff C et al. In vitro and in vivo characterization of the JAK1 selectivity of upadacitinib (ABT-494). BMC Rheumatol 2018; 2: 23]. While upadacitinib is selective for JAK2 over JAK1, anaemia is reported with upadacitinib. One case of anaemia secondary to upadacitinib in a patient with inflammatory bowel disease has been published [Shakarchi T. Profound isolated iron deficiency anemia secondary to upadacitinib in Crohn’s disease management: first reported case. Am J Gastroenterol 2024; 119 (10 Suppl.): S2527]. While clinical trials report anaemia as a side-effect of JAK inhibitors, there are no guidelines on treatment, or next steps in managing AD. Reports of treatment discontinuation due to anaemia are rare. No articles in the dermatology, rheumatology or gastroenterology literature offer advice on managing JAK inhibitor-associated anaemia, nor did we find information on restarting JAK inhibitors after resolution of anaemia outside the haematology literature. However, JAK inhibitors can safely be restarted after resolution of anaemia, which is important information in management of this complication and providing patient care.