Fungal Infections (Dermatophytosis, Tinea, Candidiasis) MCQs

Dermatology · 18 free questions with answers & explanations.

1. A 10-year-old boy presents with a boggy, tender, fluctuant mass on the scalp with multiple pustular follicular orifices and cervical lymphadenopathy. KOH preparation of hair shows endothrix pattern with arthroconidia filling the hair shaft. What is this scalp lesion called?
2. A diabetic patient presents with white creamy plaques in the oral cavity that can be easily scraped off, leaving a bleeding base. Microscopy of the scraping shows pseudohyphae and budding yeast cells. What is the drug of choice for this condition?
3. A patient with recalcitrant tinea corporis caused by Trichophyton indotineae is being evaluated. This strain is characterized by its resistance to which first-line antifungal?
4. In tinea capitis caused by Microsporum canis, the type of hair invasion and fluorescence pattern are:
5. A 35-year-old immunocompetent woman presents with white, thick, discharge per vagina with vulval itching. KOH mount shows pseudohyphae and budding yeast cells. The drug of choice for recurrent vulvovaginal candidiasis (RVVC, ≥4 episodes/year) is:
6. A patient with extensive tinea capitis shows greenish fluorescence under Wood's lamp. Which dermatophyte species is most likely responsible, and what type of hair invasion does it cause?
7. A 35-year-old immunocompromised patient on long-term corticosteroids develops extensive tinea corporis that fails to respond to topical terbinafine. Nail clippings sent for culture grow a dermatophyte with a non-pigmented, powdery colony. Which species should be suspected and why might terbinafine fail?
8. Terbinafine acts by inhibiting squalene epoxidase, causing squalene accumulation. This mechanism makes it fungicidal against dermatophytes. The LEAST effective antifungal for tinea unguium caused by Trichophyton rubrum is:
9. A 28-year-old immunocompetent man develops widespread tinea corporis over the trunk and limbs after using topical betamethasone-clotrimazole combination for a tinea lesion. The resulting clinical presentation is best described as:
10. A 10-year-old child presents with patchy alopecia with black dot pattern and fluorescence under Wood's lamp. Culture on Sabouraud's medium grows Microsporum canis. Regarding treatment, the agent of choice and duration are:
11. Widespread treatment-resistant Trichophyton indotineae infection causing extensive tinea corporis unresponsive to terbinafine has become a major concern in India. This resistance is associated with a mutation in which gene?
12. Tinea capitis in school-age children caused by Trichophyton violaceum (endothrix pattern) is treated with oral antifungals. The FIRST-LINE recommended oral antifungal for tinea capitis in children (per current guidelines) is:
13. The epidemic of recalcitrant tinea corporis in India caused by a new Trichophyton indotineae strain has raised therapeutic concern. What molecular mechanism explains its resistance to terbinafine?
14. The epidemic of recalcitrant, chronic dermatophytosis in India over the past decade is primarily attributed to which factor?
15. A diabetic patient on immunosuppressants develops black eschar on the nasal bridge with periorbital edema, proptosis, and visual loss. CT scan shows sinus involvement with orbital extension. The diagnostic test of choice and drug of choice are:
16. Widespread tinea corporis and tinea cruris resistant to multiple antifungals in India in recent years has been attributed to a hypervirulent, terbinafine-resistant strain. Which organism and mechanism is responsible?
17. A patient with extensive tinea corporis (involving >30% BSA) has failed two courses of topical antifungals and one course of griseofulvin. KOH examination consistently shows arthroconidia-forming hyphae. Which change in the pathogen's susceptibility profile most commonly accounts for treatment failure in India currently?
18. A young boy presents with a boggy, tender, fluctuant mass on the scalp with broken-off hair and cervical lymphadenopathy. Hairs are easily extracted painlessly. KOH shows endothrix pattern (spores inside hair shaft). The organism and appropriate treatment are: