Erythema nodosum is characterized by which of the following?

Erythema nodosum is indeed characterized by the presence of subcutaneous red tender nodules, primarily located on the lower extremities. This condition is an inflammatory reaction, often arising due to various underlying causes, including infections, medications, and systemic diseases. The nodules typically present as painful, raised areas on the skin, which reflect the inflammation occurring in the subcutaneous fat tissue.

The nature of these nodules, being both red and tender, distinguishes erythema nodosum from other dermatological conditions. It’s also important to note that erythema nodosum usually does not involve any scaling or significant pigmentation changes in the affected area, further emphasizing why the correct answer is related to the presence of tender nodules rather than brown pigmentation, lymphadenopathy, or scaling lesions.