**Core Concept**
Fox-Fordyce disease is a rare, chronic condition characterized by the obstruction of apocrine sweat glands, leading to the formation of comedones, papules, and plaques. This condition primarily affects the apocrine-rich areas of the body, such as the axillae, groin, and buttocks.

**Why the Correct Answer is Right**
The apocrine sweat glands are the primary targets of Fox-Fordyce disease due to their unique histological characteristics. These glands are larger and more coiled compared to eccrine glands and are primarily responsible for producing a protein-rich secretion that is high in lipids. The obstruction of apocrine glands in Fox-Fordyce disease leads to the accumulation of keratin and other cellular debris, resulting in the characteristic skin lesions.

**Why Each Wrong Option is Incorrect**
**Option A:** Eccrine sweat glands are primarily responsible for thermoregulation and are not the primary targets of Fox-Fordyce disease.
**Option C:** Sebaceous glands are responsible for the production of sebum and are not directly involved in the pathogenesis of Fox-Fordyce disease.
**Option D:** Pilosebaceous glands are a combination of hair follicles and sebaceous glands, but they are not directly related to Fox-Fordyce disease.

**Clinical Pearl / High-Yield Fact**
Fox-Fordyce disease is often associated with conditions that cause hyperkeratosis, such as chronic eczema or psoriasis. In these cases, the condition may worsen due to the increased keratinization of apocrine glands.

**✓ Correct Answer: B. Apocrine sweat glands**