Each of the following oral conditions is caused by a FUNGAL infection EXCEPT one. Which is the EXCEPTION?

Correct answer: C. Oral hairy leukoplakia

• A. ANGULAR CHEILITIS is a mixed infection at the commissures in which Candida albicans is the principal organism, frequently co-infected with Staphylococcus aureus. Treatment is a topical antifungal, often combined with correction of a reduced vertical dimension.
• B. PSEUDOMEMBRANOUS CANDIDIASIS is the archetypal oral fungal infection — Candida albicans producing curdy white plaques that WIPE OFF to leave an erythematous, sometimes bleeding base.
• C. CORRECT — this is the exception. ORAL HAIRY LEUKOPLAKIA is a VIRAL lesion caused by EPSTEIN–BARR VIRUS replicating in the epithelium. It presents as corrugated, vertically ridged white plaques on the LATERAL BORDERS OF THE TONGUE that do NOT rub off, and it occurs almost exclusively in immunosuppressed patients — classically HIV, where it is a marker of declining CD4 count, and in transplant recipients. Histology shows koilocyte-like balloon cells; the lesion does not respond to antifungals.
• D. INFLAMMATORY PAPILLARY HYPERPLASIA is a Candida-associated denture-related hyperplasia of the palatal mucosa, driven by continuous denture wear, poor hygiene and candidal colonisation.

Note: The reliable discriminator: candidal white lesions WIPE OFF (pseudomembranous) or are red (erythematous); hairy leukoplakia does NOT wipe off, sits on the lateral tongue, and is EBV. If an antifungal trial fails on a lateral tongue plaque, think EBV — or biopsy to exclude dysplasia.