**Core Concept**
Primary headaches are a group of disorders characterized by recurring headaches without any underlying structural or metabolic cause. They are typically self-limiting and not associated with other symptoms such as fever, confusion, or focal neurological deficits.

**Why the Correct Answer is Right**
The correct answer is a secondary headache, which is caused by an underlying structural or metabolic condition. This can include conditions such as meningitis, encephalitis, subarachnoid hemorrhage, or tumor. Secondary headaches often have associated symptoms such as fever, confusion, or focal neurological deficits.

**Why Each Wrong Option is Incorrect**
**Option A:** Not a cause of primary headache, as it is not a self-limiting condition.
**Option B:** Not a cause of primary headache, as it often has associated symptoms such as fever and confusion.
**Option C:** Not a cause of primary headache, as it is a condition that requires medical attention and treatment.

**Clinical Pearl / High-Yield Fact**
Primary headaches are a common cause of healthcare visits, and it is essential to differentiate them from secondary headaches to avoid missing underlying serious conditions. A thorough history and physical examination are crucial in diagnosing primary headaches.

**Correct Answer: D.**