Superficial Candidiasis
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Direct answer
Superficial candidiasis is a yeast infection of the skin and mucous membranes caused mainly by Candida albicans, affecting the mouth, skin folds and vulvovaginal area. It presents as white curdy plaques in oral thrush, erythema with satellite pustules in intertrigo and itching with curd-like discharge in vulvovaginal disease. Most cases respond to topical azoles or oral fluconazole once risk factors such as diabetes and antibiotic use are addressed.
What you must remember
- Commonest cause: Candida albicans, a dimorphic yeast; non-albicans species such as Candida glabrata may respond poorly to azoles.
- Oral thrush: white curdy plaques that scrape off to leave a red base, linked to inhaled steroids, antibiotics and dentures.
- Intertrigo: erythema in warm, moist skin folds, with satellite pustules at the margins.
- Napkin candidiasis: a beefy red rash in the diaper area, with satellite papules at its edges.
- Vulvovaginal candidiasis: itching and thick white discharge, with a normal vaginal pH.
- Recurrent disease: four or more episodes a year, which needs a longer maintenance regimen.
- Diagnosis: a potassium hydroxide mount showing pseudohyphae and budding yeasts, with culture on Sabouraud agar when needed.
- Systemic candidiasis: a separate category, including candidaemia, which needs intravenous antifungal therapy.
Matching the site to the features
A diabetic woman on a course of antibiotics develops itching, thick white discharge and a normal vaginal pH, while her infant has white plaques on the tongue. The table sets out the sites, signs and first-line treatment, which the examiner expects you to match quickly.
| Site | Clinical sign | First-line treatment |
|---|---|---|
| Oral thrush | White curdy plaques that scrape off | Topical nystatin or clotrimazole; fluconazole if severe |
| Intertrigo | Erythema with satellite pustules | Keep folds dry; topical azole |
| Napkin candidiasis | Beefy red rash in the diaper area | Topical azole; treat the moisture |
| Vulvovaginal candidiasis | Itch and curd-like discharge | Single-dose oral fluconazole, or topical azole |
Treatment should address the predisposing factor as well as the infection. Keeping folds dry, controlling diabetes and reviewing unnecessary antibiotics or steroids reduces recurrence more reliably than antifungals alone. Pregnancy changes the choice of agent, as oral azoles are generally avoided in early pregnancy and topical therapy is preferred.
Where the exam tries to catch you
Questions on this topic usually test the discharge pattern, the vaginal pH and the rules of treatment for uncomplicated disease.
- Trap: a fishy-smelling discharge indicates candidiasis. Correct: a fishy odour suggests bacterial vaginosis, whereas candidiasis is typically itchy with a curdy discharge and no odour.
- Trap: every white oral plaque needs a biopsy. Correct: pseudomembranous thrush scrapes off, and only non-removable, persistent plaques need further evaluation.
- Trap: the vaginal pH is raised in candidiasis. Correct: pH stays normal in uncomplicated candidiasis, unlike bacterial vaginosis or trichomoniasis.
- Trap: every case needs systemic antifungals. Correct: superficial disease is treated topically or with a single oral dose of fluconazole, and systemic therapy is reserved for invasive infection.
Frequently asked questions
What is the typical discharge of vulvovaginal candidiasis?
Vulvovaginal candidiasis typically causes itching, soreness and a thick, curdy white discharge without odour. The vaginal pH is usually normal, which helps distinguish it from bacterial vaginosis. A potassium hydroxide mount showing pseudohyphae or budding yeast confirms the diagnosis.
Which Candida species is the most common cause of superficial candidiasis?
Candida albicans is the most common cause of superficial candidiasis, although non-albicans species such as Candida glabrata are increasingly recognised. Non-albicans species may respond less well to azoles. Culture is needed when the response to first-line treatment is poor.
What is the first-line treatment for uncomplicated vulvovaginal candidiasis?
Uncomplicated vulvovaginal candidiasis is treated with a single 150 mg oral dose of fluconazole, or with a short course of a topical azole. Recurrent disease, defined as four or more episodes a year, needs a longer maintenance regimen. Routine treatment of sexual partners is not required.
Why is intertrigo associated with candidiasis?
Intertrigo is associated with candidiasis because warm, moist skin folds favour yeast growth. Candida produces erythema with satellite pustules at the margins of the fold. Topical azoles and keeping the folds dry are the main treatments, and the cause of moisture, such as obesity or diabetes, should be addressed.
What are the risk factors for oral candidiasis?
Oral candidiasis is linked to inhaled or systemic corticosteroids, broad-spectrum antibiotics, diabetes, dentures, HIV infection and infancy. Xerostomia and malnutrition also contribute to the risk. Identifying the cause helps guide therapy and prevent recurrence.