key: cord-0850574-bu4gxu6n authors: Wu, Xiaotian; Liang, Joel Lim Hua; Siong See, Joyce Lee; Chio, Martin TW. title: Recurrent erythema nodosum after second dose of the Pfizer-BioNTech BNT162b2 COVID-19 messenger RNA vaccine date: 2021-12-28 journal: JAAD Int DOI: 10.1016/j.jdin.2021.12.009 sha: 102d6613e1b71ffdc14e3e2659bc62ae7ee8b67d doc_id: 850574 cord_uid: bu4gxu6n Vaccine induced erythema nodosum (EN) is well recognized. In this letter, we report a case of a patient who developed recurrent EN following vaccination with the Pfizer-BioNTech BNT162b2 COVID-19 messenger RNA (mRNA) vaccine. Clinicians should be aware that COVID-19 mRNA vaccines can be a possible cause of EN. A 37-year-old Burmese female presented with a six week duration of tender nodules on her 2 distal legs which appeared a day after receiving her second tozinameran vaccination. She 3 previously had erythema nodosum (EN) ten years ago, which was related to pulmonary 4 tuberculosis (PTB). She had completed treatment for PTB then, and there was complete 5 resolution of the prior episode of EN till time of presentation. A computed tomography (CT) 6 scan of her thorax done several months prior showed no evidence of active PTB and a thorough 7 review of systems was unyielding. Her medical history is significant for well controlled 8 Hashimoto's thyroiditis. 9 On examination, there were erythematous, tender, non-ulcerative deep nodules around both 11 knees, right shin and above the left lateral malleolus (Figure 1) . A lesional punch biopsy 12 revealed septal panniculitis with granulomatous aggregates of foreign body-type 13 multinucleated giant cells, histiocytes, and lymphocytes (Figure 2A MBBS, MRCP (UK), MMed (Int. Med), FAMS (Dermatology), Dip.Dermatopathology (ICDP-UEMS) MSc (Lond), MRCP (UK), FRCP (Lond), FAMS (Dermatology) Tumour necrosis factor-alpha promoter polymorphism in erythema nodosum COVID-19 vaccine BNT162b1 elicits human antibody and TH1 T cell responses TNF-alpha in tuberculosis: a cytokine with a split personality POS0422 Panniculitis as a manifestation of an autoimmune/autoinflammatory disease The ASIA syndrome: basic concepts