Alternaria vs Curvularia: Dematiaceous Conidia
Original bench-card visual comparing two dematiaceous molds: Alternaria muriform conidia with a tapered beak versus Curvularia curved conidia with a swollen central cell.
Dematiaceous molds: Alternaria beaked muriform vs Curvularia curved conidia
Both are pigmented (dematiaceous) molds with brown septate hyphae. Conidial shape separates them: Alternaria is muriform with a beak, Curvularia is curved with a larger central cell.
Conidia are muriform, divided by both crosswise and lengthwise septa, and taper into a beak-like extension. Chains often form in branching arrangements.
Conidia are curved by an enlarged central cell that bends the conidium. Cross septa divide it, but there are no lengthwise septa and no beak.
Conidia are muriform, divided by both crosswise and lengthwise septa, and taper into a beak-like extension. Chains often form in branching arrangements.
Conidia are curved by an enlarged central cell that bends the conidium. Cross septa divide it, but there are no lengthwise septa and no beak.
Dematiaceous comparison anchors
| Visual clue | Meaning | Student shorthand |
|---|---|---|
| Brown septate hyphae | Dematiaceous group | Pigment is visible without staining; places both in the dark-mold group |
| Muriform conidia with a beak | Alternaria pattern | Crosswise and lengthwise septa plus a tapered beak |
| Curved conidia, swollen central cell | Curvularia pattern | Central cell enlargement bends the conidium |
| Sterile site or sinus source | Clinical context | Significance depends on source and host; interpret per SOP |
Dematiaceous interpretation guide
| Pattern | What to call it | How to think about it |
|---|---|---|
| Muriform beaked conidia, brown hyphae | Alternaria-compatible morphology | Confirm by validated mold ID workflow |
| Curved conidia with swollen central cell | Curvularia-compatible morphology | Confirm by validated mold ID workflow |
| Hyaline septate hyphae, no pigment | Not dematiaceous | Reconsider Aspergillus, Fusarium, or Scedosporium |
- Both are dematiaceous molds with brown septate hyphae.
- Alternaria conidia are muriform with a beak; Curvularia conidia are curved by a swollen central cell.
- Clinical significance depends on specimen source and host context.
Alternaria = beaked muriform conidia. Curvularia = curved conidia with a swollen central cell.