Fungal Thigmotropism in Onychomycosis and in a Clear Hydrogel Pad Model

Background: Thigmotropism is a biological characteristic corresponding to the directional growth of cells following topographical guidance cues. This behavior has been shown experimentally with fungal hyphae of both dermatophytes and nondermatophyte molds, as well as with the mycelial phase of the dimorphic yeast Candida albicans. Objective and Methods: We presently document this phenomenon using histomycology in onychomycoses of various fungal origins. Results: This mechanism is involved in the invasive phase of the pathogen or opportunistic fungi, and it probably governs various clinical aspects of onychomycoses. We incidentally disclosed fungal invasions of hydrogel pads. Conclusion: Thigmotropism can in part explain the diversity of orientations and shapes of fungi invading nail plates. The same phenomenon was disclosed inside hydrogel pads. As this material is transparent and easy to cut for microscopic examination, fungal thigmotropism is conveniently explored by this way.