**Core Concept**
Seborrheic dermatitis, lytic skull lesions, ear discharge, and hepatosplenomegaly are a constellation of symptoms that suggest a systemic disease affecting multiple organ systems. This presentation is classic for a condition that involves both the skin and the bones, with potential involvement of the lymphoid system.

**Why the Correct Answer is Right**
The correct diagnosis is **Histoplasmosis**. This fungal infection is caused by **Histoplasma capsulatum**, which is typically acquired through inhalation of spores. The organism initially affects the lungs but can disseminate to other organs, including the skin, bones, and lymphoid tissues. Seborrheic dermatitis is thought to be an extracutaneous manifestation of histoplasmosis. The lytic skull lesions are due to the direct invasion of the organism into the bone marrow. Ear discharge may be a result of the spread of the infection to the middle ear. Hepatosplenomegaly is a sign of the organism's spread to the lymphoid organs.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
Histoplasmosis should be considered in the differential diagnosis of patients presenting with seborrheic dermatitis and lytic bone lesions, especially in endemic areas. A high index of suspicion, along with appropriate laboratory tests, is crucial for making an early diagnosis.

**Correct Answer:** D. Histoplasmosis.