Which dermatophyte is the second most common cause of infections including pedis, corporis, cruris, and onychomycosis?

Which dermatophyte is the second most common cause of infections including pedis, corporis, cruris, and onychomycosis?

• A. Microsporum audouii
• B. Malassezia furfur
• C. Trichophyton tonsurans
• D. Trichophyton rubrum

Answer: (D)

In these dermatophyte infections the usual pattern is that one species is the most frequent offender across sites like feet, body, groin, and nails, with another species close behind as the next common cause. The organism that most often drives pedis, corporis, cruris, and onychomycosis is Trichophyton rubrum. It tends to colonize keratinized tissues broadly and persist chronic infections, making it the leading cause. The next most frequent culprit is Trichophyton mentagrophytes (including members of the mentagrophytes/interdigitale complex). It also readily infects keratinized tissues but is encountered less often than rubrum, hence its rank as the second most common. Malassezia furfur causes tinea versicolor, not these dermatophyte infections. Microsporum audouinii and Trichophyton tonsurans are more strongly associated with tinea capitis in many populations, so they are less typical as the second most common causes of pedis, cruris, corporis, and onychomycosis. Therefore, the second most common cause among these infections is Trichophyton mentagrophytes.

In these dermatophyte infections the usual pattern is that one species is the most frequent offender across sites like feet, body, groin, and nails, with another species close behind as the next common cause. The organism that most often drives pedis, corporis, cruris, and onychomycosis is Trichophyton rubrum. It tends to colonize keratinized tissues broadly and persist chronic infections, making it the leading cause.

The next most frequent culprit is Trichophyton mentagrophytes (including members of the mentagrophytes/interdigitale complex). It also readily infects keratinized tissues but is encountered less often than rubrum, hence its rank as the second most common.

Malassezia furfur causes tinea versicolor, not these dermatophyte infections. Microsporum audouinii and Trichophyton tonsurans are more strongly associated with tinea capitis in many populations, so they are less typical as the second most common causes of pedis, cruris, corporis, and onychomycosis.

Therefore, the second most common cause among these infections is Trichophyton mentagrophytes.