## **Core Concept**
The question tests knowledge of drug-induced lupus erythematosus (DILE), a condition similar to systemic lupus erythematosus (SLE) but caused by certain medications. DILE is characterized by the presence of antinuclear antibodies (ANA) and clinical symptoms such as rash, joint pain, and serositis. The key to this question is identifying which antihypertensive medication is commonly associated with DILE.

## **Why the Correct Answer is Right**
The correct answer, **C. Hydralazine**, is a well-known cause of drug-induced lupus erythematosus. Hydralazine is a vasodilator used in the treatment of hypertension. It can induce an autoimmune response leading to DILE in some patients. The symptoms described, such as fatigue, rash, joint aches, effusions, and a positive ANA test, are consistent with DILE. The mechanism behind DILE involves the drug or its metabolites acting as haptens, leading to an immune response.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is blank and cannot be evaluated.
- **Option B:** This option is blank and cannot be evaluated.
- **Option D:** This option is blank and cannot be evaluated.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that drug-induced lupus erythematosus is often associated with **Hydralazine** and **Procainamide**, two medications that have been commonly implicated in causing this condition. The presence of a positive ANA test in a patient with symptoms suggestive of lupus, especially in the context of recent medication initiation, should prompt consideration of DILE.

## **Correct Answer: C. Hydralazine**