Dermatophyte Comparison: Trichophyton, Microsporum, Epidermophyton
Original bench-card comparison for dermatophyte morphology: microconidia-heavy Trichophyton, spindle macroconidia of Microsporum, and club-shaped macroconidia of Epidermophyton.
Dermatophyte comparison: microconidia and macroconidia shapes
Read dermatophytes as a pattern comparison. Trichophyton often leans on microconidia, Microsporum has rough spindle macroconidia, and Epidermophyton has smooth club-shaped macroconidia without microconidia.
Many species show microconidia along hyphae; macroconidia may be rare or absent depending on species and medium.
Large spindle-shaped, rough-walled macroconidia are the classic Microsporum anchor. Microconidia may be present but are not the main clue.
Smooth, club-shaped macroconidia often occur in clusters. Microconidia are absent, which helps separate it from the other two genera.
Many species show microconidia along hyphae; macroconidia may be rare or absent depending on species and medium.
Large spindle-shaped, rough-walled macroconidia are the classic Microsporum anchor. Microconidia may be present but are not the main clue.
Smooth, club-shaped macroconidia often occur in clusters. Microconidia are absent, which helps separate it from the other two genera.
Dermatophyte genus anchors
| Visual clue | Meaning | Student shorthand |
|---|---|---|
| Many microconidia | Trichophyton pattern | Macroconidia may be rare, pencil-shaped, or species-dependent |
| Rough spindle macroconidia | Microsporum pattern | Usually the most visually distinctive macroconidia group |
| Smooth club macroconidia | Epidermophyton pattern | No microconidia is the key negative clue |
| Hair, skin, nail source | Dermatophyte context | Match morphology with clinical specimen and culture features |
Dermatophyte comparison guide
| Pattern | What to call it | How to think about it |
|---|---|---|
| Microconidia dominate | Trichophyton likely | Review arrangement: singly along hyphae, clusters, or grape-like groups |
| Spindle rough macroconidia | Microsporum likely | Use macroconidia wall texture and shape |
| Club macroconidia, no microconidia | Epidermophyton likely | Absence of microconidia is part of the call |
- Dermatophyte comparison is a shape language: microconidia, spindle macroconidia, or club macroconidia.
- The best student move is to compare the genus-level anchors before memorizing species exceptions.
- Poor sporulation is common, so weak mounts should trigger better prep or confirmatory workflow.
Trichophyton = microconidia. Microsporum = spindle macroconidia. Epidermophyton = club macroconidia with no microconidia.