**Core Concept**
Epidermophyton is a genus of fungi that primarily infects skin and nails, causing conditions like tinea cruris (jock itch) and tinea pedis (athlete's foot). Unlike other options, Epidermophyton species do not infect hair.

**Why the Correct Answer is Right**
Epidermophyton species, such as Epidermophyton floccosum, are known to infect keratinized tissues like skin and nails but do not typically infect hair. This is because hair is composed of a different type of keratin, which is less susceptible to infection by Epidermophyton species. In contrast, Microsporum and Trichophyton species are well-known to infect hair, causing conditions like tinea capitis (ringworm of the scalp).

**Why Each Wrong Option is Incorrect**
**Option B:** Microsporum species, such as Microsporum canis, are common causes of tinea capitis and tinea corporis, and can infect hair.
**Option C:** Trichophyton species, such as Trichophyton tonsurans, are also known to infect hair and cause conditions like tinea capitis.
**Option D:** Trichosporon species can infect various tissues, including hair, particularly in immunocompromised individuals.

**Clinical Pearl / High-Yield Fact**
Remember that Epidermophyton species are not typically associated with hair infections, making them a key differentiator from other dermatophytes.

**✓ Correct Answer: A. Epidermophyton**