“…While many cases of OPN are idiopathic (primary OPN), most are secondary to an identifiable systemic disease [ 3 ], for which OPN is sometimes the initial presenting feature. Systemic associations for secondary OPN include inflammatory conditions such as Crohn's disease [ 4 ], sarcoidosis [ 3 , 5 , 6 ], Behçet disease [ 7 ], granulomatosis with polyangiitis [ 8 ], giant cell arteritis [ 3 , 9 ], and myelin oligodendrocyte glycoprotein antibody disease [ 3 ]. OPN can also occur in association with infections such as syphilis [ 3 , 10 , 11 , 12 ], tuberculosis [ 13 ], or COVID-19 [ 3 , 14 ].…”