Subacute nodular migratory panniculitis (SNMP), also known as Vilanova disease, is a rarely encountered variant of erythema nodosum characterized by asymmetric, mildly tender nodules on the lower extremities. The condition, which predominantly affects women in the third to sixth decades of life, typically presents as a single erythematous to brownish nodule on the anterolateral shin. Over time, the lesion often enlarges by peripheral expansion and evolves to form a larger indurated plaque. The plaque does not ulcerate or drain but typically becomes crescentic or arcuate in nature. If left untreated, the lesions of SNMP can persist for months or years and rarely regress spontaneously.

No definitive cause of SNMP has been identified, and the majority of cases appear to be idiopathic. Some case reports have suggested infectious etiologies (particularly streptococcal pharyngitis) and predisposing thyroid disease.