Rheumatoid arthritis is a systemic autoimmune disease resulting in joint destruction and deformities, but also associated with extraarticular and systemic manifestations. The later devastating conditions, such as the development of rheumatoid vasculitis, are more frequently encountered in seropositive patients and their incidence has been attenuated after the introduction of biologic disease modifying drugs, such as anti-tumor necrosis factor alpha (TNFa) agents, which generally have considerably contributed to the better control and long-term outcomes of the disease. Interestingly, autoimmune syndromes may, rarely, present in patients without a positive history after the initiation of treatment. We present a rare case of a woman with seronegative rheumatoid arthritis who developed pyoderma gangrenosum whistle on treatment with golimumab, a fully humanized anti TNFa antibody. The recording of this as well as analogous paradoxical autoimmune syndromes in association with the individual patient characteristics will render treating physicians aware of potential adverse reactions and assist in the understanding of the cytokine driven pathophysiological mechanisms underlying these disorders.