From the Guidelines
The presence of hyphae on a wet mount is a significant finding that suggests a fungal infection, particularly candidiasis, and is a crucial diagnostic tool in clinical practice. Hyphae are fungal structures that appear as long, branching filaments when viewed under a microscope. To perform a wet mount examination for hyphae, place the specimen (vaginal discharge or other tissue) on a glass slide, add a drop of 10% potassium hydroxide (KOH) solution to dissolve keratin and cellular debris, apply a coverslip, and gently heat the slide. After cooling, examine under a microscope at 10x and 40x magnification.
Key Points to Consider
- The observation of pseudohyphae can help to detect the infection, but filaments can be observed in patients without infection 1.
- Not all Candida species form filaments during infection (e.g., C. glabrata), and microscopy in such cases will show only yeast cells 1.
- The use of 10% KOH in wet preparations improves the visualization of yeast and mycelia by disrupting cellular material that might obscure the yeast or pseudohyphae 1.
- A diagnosis of vulvovaginal candidiasis can usually be made clinically when a woman presents with symptoms of pruritus, irritation, vaginal soreness, external dysuria, and dyspareunia, often accompanied by a change in vaginal discharge, and can be confirmed by a wet-mount preparation with use of saline and 10% potassium hydroxide to demonstrate the presence of yeast or hyphae and a normal pH (4.0–4.5) 1.
Diagnostic Approach
- Examination of vaginal secretions is very valuable in detecting Candida vaginitis, and the observation of pseudohyphae can help to detect the infection 1.
- Culture of swabs and vaginal secretions are also essential investigations, and semi-quantitative techniques using fungal selective agar are recommended 1.
- Species identification and susceptibility testing are indicated in recurrent/complicated cases and in patients with prior azole exposure 1.