145. Reactive arthritis secondary to mRNA vaccine with urticarial skin lesions with reversible rheumatoid serology

Background: A 20-year-old female presented with swelling of hands and feet. 3 days earlier she received mRNA BNT162b2 vaccine. She had swollen lips (Fig. 1A), right ankle, (Fig. 1B), wrists and MCP joints (Fig. 1C). She developed urticarial-rash affecting her legs (Fig. 1D). Methods: Her bloods revealed elevated CRP 138mg/L. Despite prednisolone 40mg daily she developed dyspnoea, pruritus, angioedema requiring IM adrenaline, IV chlorphenamine and hydrocortisone. Blood and urine cultures, Coronavirus PCR, Influenza and RSV were negative. Results: HLA B27, hepatitis B, C, chlamydia, gonorrhoea and HIV were negative. RF and anti-CCP were elevated at 20.2IU/ml [Normal