Black Piedra is caused by:
**Core Concept**
Black Piedra is a type of fungal infection that affects the hair shaft, particularly in tropical and subtropical regions. It is characterized by the formation of hard, black nodules on the hair, which can cause discomfort and aesthetic concerns.
**Why the Correct Answer is Right**
The correct answer is **Piedraia hortae**, a species of fungus that specifically colonizes the hair shaft, leading to the characteristic black nodules. This fungus thrives in warm, humid environments and can be transmitted through direct contact with infected hair or contaminated water. The infection is typically localized to the scalp or beard area.
**Why Each Wrong Option is Incorrect**
* **Option A:** Trichophyton mentagrophytes is a dermatophyte fungus that causes skin and hair infections, but it is not responsible for Black Piedra.
* **Option B:** Epidermophyton floccosum is another dermatophyte fungus that causes skin and nail infections, but it is not associated with Black Piedra.
* **Option C:** Malassezia species are yeasts that are commonly found on the skin and scalp, but they are not responsible for Black Piedra.
**Clinical Pearl / High-Yield Fact**
To diagnose Black Piedra, clinicians should look for characteristic black nodules on the hair shaft, particularly in individuals with a history of exposure to warm, humid environments.
**Correct Answer:** C.