**Core Concept**
Erythema nodosum is a type of skin condition characterized by the formation of painful, red nodules on the skin, typically on the lower legs. It is often associated with various underlying conditions, including infections, autoimmune disorders, and medications.

**Why the Correct Answer is Right**
Erythema nodosum is commonly linked to infections such as tuberculosis, streptococcal pharyngitis, and inflammatory bowel disease. It is also associated with autoimmune disorders like sarcoidosis and lupus. In addition, certain medications, including sulfonamides and oral contraceptives, can trigger the development of erythema nodosum. The exact cause is often unclear, but it is thought to result from a combination of genetic predisposition and environmental triggers.

**Why Each Wrong Option is Incorrect**
**Option A:** While certain medications can trigger erythema nodosum, option A is not a correct answer as this option is not provided.
**Option B:** Not provided in the question.
**Option C:** Not provided in the question.

**Clinical Pearl / High-Yield Fact**
It is essential to consider erythema nodosum in the differential diagnosis of patients presenting with skin nodules on the lower legs, especially in the context of underlying infections, autoimmune disorders, or medication use.

**Correct Answer: None**