Chronic Erythema Nodosum Circumstantially Linked with <i>Helicobacter pylori</i> Infection: Where Is the Evidence?

lymphomas can rarely cause EN as well [2, 7] , including 1 case of gastric centrofollicular lymphoma [7] . However, this was reported in 1989, when laboratory investigations for Hp I were not readily available. (4) Semi-experimental evidence: EN disappeared after triple treatment of Hp I. Other causes of EN (either infectious or noninfectious ones), which, being sensitive to clarithomycin, metronidazole or lansoprazole, could act as hypothetical confounders, have never been demonstrated in these patients. (5) Temporality: this is an unarguable criterion [3] . Given the fact that it has not been demonstrated that HpI cannot precede EN, the current hypothesis that HpI can cause EN cannot be dispensed with to date. This topic clearly needs further studies. Practical clinicians could contribute to address stronger causality tenets [3] from an observational viewpoint, by prescribing relatively inexpensive H. pylori laboratory investigations and therapy to patients presenting with unexplained EN.