## **Core Concept**
Fixed drug eruptions (FDEs) are a type of cutaneous adverse drug reaction characterized by the appearance of skin lesions at the same site each time the offending drug is administered. This condition is often associated with certain medications that trigger an immune response.

## **Why the Correct Answer is Right**
The correct answer, **D. NSAIDs**, is right because Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) are among the common culprits known to cause fixed drug eruptions. NSAIDs, such as ibuprofen, naproxen, and mefenamic acid, can induce an immune-mediated response leading to FDEs. The mechanism likely involves the activation of T lymphocytes and the release of cytokines, which cause skin damage.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While certain antibiotics can cause FDEs, they are not as frequently associated with this condition as NSAIDs.
- **Option B:** Antihistamines are not commonly linked to FDEs; they are more often used to treat allergic reactions.
- **Option C:** Anticonvulsants can cause various skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, but are less commonly associated with FDEs compared to NSAIDs.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the most common drugs causing fixed drug eruptions include **NSAIDs**, **antibiotics (especially sulfonamides)**, and **anticonvulsants**. Clinicians should be cautious when prescribing these medications, especially in patients with a history of similar reactions.

## **Correct Answer:** D. NSAIDs.