Drug-Induced Lupus or Systemic Lupus Erythematosus After Experimental COVID-19 Therapy: Difficulties in Differential Diagnosis

A 60-year-old patient developed drug-induced lupus erythematosus (DIL) after receiving a combination of monoclonal antibodies against the SARS-CoV-2 surface S-protein. Initially diagnosed with seronegative rheumatoid arthritis, the patient experienced recurring arthritis and was treated with various medications. After mild COVID-19 and subsequent monoclonal antibody therapy, the patient developed a urticaria-like rash and arthritis. Laboratory tests indicated systemic lupus erythematosus (SLE), but the diagnosis was considered DIL due to the timing of symptoms and lack of visceral organ involvement. Treatment led to a reduction in symptoms. This case highlights the challenge of distinguishing DIL from SLE and the need for careful patient monitoring.