Yeast Infections
Unlike dermatophytes, which are superficial molds adapted to live only on keratin, yeasts of the genus Candida (chiefly Candida albicans) are opportunistic organisms that normally live as part of the natural flora of the gut, vagina and moist areas of human skin.
In a healthy state, the immune system and competition from resident bacteria keep Candida in its harmless single-celled form. Once the skin barrier is damaged, however, and other factors come into play, such as heat and humidity, diabetes, weakened immunity, long courses of broad-spectrum antibiotics or overuse of topical or oral corticosteroids, the yeast multiplies rapidly, becomes more invasive and can cause a wide range of skin and mucosal infections.
At Haute-Derma, our diagnostic workup for yeast infections follows medical standards to reliably distinguish Candida from dermatophytes and bacteria, while clearing the fungal reservoirs hidden in body folds to prevent stubborn recurrences.
Microbiology and the Switch to Virulence
- Dimorphism (morphological transition):
- As a harmless commensal, C. albicans exists as round or oval single-celled yeasts (blastoconidia).
- Under favorable conditions (37°C, a rise in pH, an environment rich in sugar or lipids, or a broken skin barrier), it switches on signaling pathways that convert it into pseudohyphae and true hyphae. These filamentous forms can push through the membranes of epidermal cells.
- Extracellular virulence enzymes: The yeast secretes aspartyl proteinases (SAPs) that break down collagen and fibronectin, along with phospholipases that damage keratinocyte membranes. This sets off acute inflammation with oozing, pustule formation and irritation of sensory nerves (intense itching, burning pain).
- Causative species: Candida albicans accounts for 80%–90% of cases. However, non-albicans Candida (NAC) species such as C. tropicalis, C. parapsilosis, C. glabrata and C. krusei are becoming more common, especially in people with diabetes or those whose previous antifungal treatment failed, because NAC species have higher rates of intrinsic resistance to azoles.
Our Diagnostic Process at Haute-Derma
Digital Dermoscopy:
- Candidal intertrigo: A bright red, oozing base, a ring of peeling scale at the edge and satellite pustules, each with a red halo.
- Paronychia: Loss of the cuticle and glomerular vessels along the nail fold.
Direct Microscopy with 10–20% KOH and Calcofluor White Staining:
- We collect pus or skin scrapings from the edge of the satellite pustules.
- Under the fluorescence microscope, we see numerous budding yeast cells (blastoconidia) 2–6 µm across, together with long chains of pseudohyphae.
Wood's Lamp Examination: Shining the lamp directly on the skin folds quickly rules out erythrasma (caused by Corynebacterium minutissimum, which glows coral red) and Pseudomonas infection (which glows green).
SDA Culture and Species Identification: Recommended for recurrent infections, failure of a standard azole regimen, or suspected drug-resistant non-albicans Candida species. Candida colonies grow quickly, appearing within 24–48 hours as soft, creamy white clusters.
Comprehensive Treatment at Haute-Derma
Topical Antifungal Therapy:
- Drying and barrier protection (essential for intertrigo): Zinc oxide paste, talc powder or Castellani's paint applied to the folds twice daily reduces friction and absorbs moisture.
- Antifungal creams and solutions:
- Nystatin cream (highly active against Candida), ciclopirox olamine 1%, clotrimazole 1%, econazole 1% or sertaconazole 2%: apply twice daily for 2–3 weeks.
- For paronychia: apply an antifungal cream and drop iodine tincture or Castellani's paint deep into the nail fold.
Systemic Therapy:
- Indications: Widespread Candida infection, chronic mucosal disease, severe paronychia, or patients with underlying diabetes or immunosuppression.
- Fluconazole (first choice):
- Intertrigo or paronychia: 150 mg once a week for 2–4 weeks (or 50 mg daily for 7–14 days).
- Oral thrush or angular cheilitis: 150 mg daily for 7–14 days.
- Itraconazole: 200 mg daily for 7–14 days (or pulse dosing of 400 mg daily in two divided doses for 1 week each month for Candida nail infection).
Controlling Risk Factors and Preventing Recurrence:
- Blood sugar control: Patients with diabetes should keep their HbA1c below 7.0%.
- Everyday habits: Wear cotton-lined rubber gloves for wet work, and dry skin folds thoroughly with a clean towel or a cool fan after bathing.
- Stop misusing corticosteroids: Do not self-treat with unlabeled triple-combination creams (corticosteroid + antibiotic + antifungal).
