Our study has shown that the course of early LB in patients receiving TNF inhibitors, often in combination with other immunosuppressants, somewhat differs from that in immunocompetent patients and that using an identical antibiotic treatment approach as for immunocompetent patients with EM, while continuing treatment with a TNF-α inhibitor, resulted in more common treatment failure and more often a complicated course of LB in patients receiving a TNF-α inhibitor than in sex- and age-matched immunocompetent patients with EM. Here, TNF is linked to erythema multiforme.