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DR7.1-2 | Fungal Infections — Graded Quiz
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A 28-year-old medical student presents to the dermatology OPD with a 6-week history of hypopigmented macules on the trunk and upper arms, which became noticeable after sun exposure. Skin scrapings are taken and examined under 20% KOH with ink. The image below is described: clustered short curved hyphae and round spore clusters on a background of squamous epithelium. She has no systemic illness. What is the MOST appropriate management?
Correct. Tinea versicolor is caused by Malassezia, a yeast not a dermatophyte. Terbinafine (which targets dermatophytes) is NOT effective against Malassezia. Topical ketoconazole shampoo applied as a body wash is a standard, effective treatment. Counsel the patient that hypopigmentation persists for months after mycological cure — repigmentation follows sun exposure.
Pityriasis versicolor (tinea versicolor) caused by Malassezia furfur presents as hypo/hyperpigmented macules on sun-exposed trunk. KOH shows spaghetti-and-meatballs. First-line is topical antifungal (ketoconazole shampoo, selenium sulfide, or single-dose oral fluconazole/itraconazole for extensive disease). Terbinafine is NOT effective against Malassezia. Repigmentation is slow after mycological cure.
This is pityriasis versicolor (Malassezia furfur). Key trap: Terbinafine is effective against dermatophytes but NOT Malassezia. Treatment is topical ketoconazole/selenium sulfide or a single dose of oral itraconazole/fluconazole for extensive disease. Repigmentation is slow — occurs over months after successful treatment.
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You are examining a KOH preparation from the nail of a 55-year-old with dystrophic toenails. The slide shows thick, irregular, branching hyphae with some budding. Your senior colleague reviews and says this is 'a high-quality mount — the only issue is you have an artefact mixed in.' The artefact they are referring to shows which feature?
Correct. The key distinguishing feature of mosaic fungus artefact is that the refractile lines cross keratinocyte cell boundaries in a geometric pattern. True fungal hyphae respect cell boundaries. Septations, branching, and budding are genuine fungal findings, not artefacts.
Mosaic fungus artefact consists of cell wall junction lines that cross keratinocyte boundaries — true hyphae do not cross cell boundaries. They are perfectly straight, perfectly uniform in width, and form geometric grid patterns. Septa in true hyphae, branching, and budding yeast are all genuine findings.
Mosaic fungus artefact is identified by structures crossing keratinocyte cell boundaries in a straight, geometric pattern. Genuine hyphae remain within cells. Septations, branching, and budding are all real fungal features. Green fluorescence is not a standard KOH bright-field finding.
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A 30-year-old pregnant woman (32 weeks gestation) presents with extensive tinea corporis unresponsive to 6 weeks of topical clotrimazole. KOH confirms septate hyphae. You decide systemic therapy is necessary. Which of the following is the MOST appropriate systemic antifungal to prescribe in this context?
Correct. No systemic antifungal used for tinea is clearly safe in pregnancy at standard doses. Itraconazole is teratogenic in animal studies; fluconazole has dose-dependent teratogenicity concerns; terbinafine has insufficient safety data. The correct approach is to optimise topical therapy (clotrimazole, miconazole, naftifine are category B/C but applied topically) and refer to a dermatologist if disease is severe.
All systemic antifungals commonly used for dermatophytosis carry significant pregnancy concerns: terbinafine (limited data, generally avoided in pregnancy), itraconazole (teratogenic in animals, avoid especially in first trimester), fluconazole (associated with fetal defects at higher doses, high-dose use restricted). For tinea in pregnancy, optimise topical therapy; if systemic therapy is unavoidable, refer to a dermatologist for specialist input.
All common systemic antifungals (terbinafine, itraconazole, fluconazole) carry significant pregnancy risk: itraconazole is teratogenic in animals, fluconazole has dose-related fetal risk, and terbinafine has insufficient data. The safe management is to maximise topical therapy and refer for specialist input. Do not prescribe systemic antifungals for tinea in pregnancy without specialist guidance.
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A 10-year-old boy presents with a 3 cm boggy, painful, purulent scalp mass with overlying hair loss and multiple draining sinuses. Regional lymph nodes are enlarged. KOH of hair shows ectothrix pattern (spores on the outside of the hair shaft). What is this condition called, and what is the treatment?
Correct. Kerion celsi is an intense inflammatory mass caused by a hypersensitivity reaction to dermatophyte infection of the scalp. It is NOT a bacterial infection and should NOT be incised. Treatment: oral antifungal (griseofulvin 20 mg/kg/day or terbinafine weight-based for 6–8 weeks); add short-course oral prednisolone to reduce scarring alopecia risk.
Kerion is the severe inflammatory response to tinea capitis — a boggy, painful, sterile abscess-like mass with sinus tracts caused by a hypersensitivity reaction to dermatophyte antigens. Treatment is systemic antifungal (oral griseofulvin or terbinafine). Do NOT incise and drain (not a bacterial abscess); oral steroids may be added to reduce scarring alopecia risk.
This is kerion — an intense host immune response to tinea capitis, not a bacterial abscess. Incision and drainage is WRONG and will worsen scarring. Treatment is oral antifungal (griseofulvin or terbinafine) ± short-course steroids to prevent permanent scarring alopecia.
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While reviewing a KOH mount from a vaginal discharge, you observe structures that resemble pseudohyphae — elongated chains of blastospores with visible constrictions at junction points, along with single budding yeast cells. The patient is a 25-year-old woman with thick white 'cottage cheese' vaginal discharge, vulval pruritus, and erythema. What is the COMPLETE management?
Correct. Vulvovaginal candidiasis is treated with single-dose intravaginal clotrimazole 500 mg or oral fluconazole 150 mg. Terbinafine is ineffective against Candida. Routine partner treatment is not recommended. Investigate for predisposing factors (diabetes, antibiotic use, immunosuppression) in recurrent cases.
Vulvovaginal candidiasis: pseudohyphae + budding yeast on KOH plus classic symptoms. Treatment: single-dose intravaginal clotrimazole 500 mg pessary OR oral fluconazole 150 mg. Terbinafine has minimal activity against Candida. Partner treatment is NOT routine (Candida is not a classic STI); treat partner only if recurrent/symptomatic.
Pseudohyphae + budding yeast = Candida, causing vulvovaginal candidiasis. Treat with single-dose intravaginal clotrimazole or oral fluconazole. Metronidazole treats bacterial vaginosis. Terbinafine does NOT cover Candida. Spontaneous resolution is unreliable and the patient needs treatment.
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A 16-year-old male presents with hypopigmented annular patches on the trunk for 3 months. His classmates have similar lesions. KOH shows septate, branching hyphae. The lesions show NO fluorescence on Wood's lamp examination. Tinea corporis is confirmed. During history, he mentions he has been applying 'an OTC cream from the pharmacist' — on examination there are multiple polycyclic patches with a blurred, non-distinct border. The SINGLE most important public-health action beyond treating this patient is:
Correct. The cluster of cases in classmates indicates person-to-person spread. The key actions are: stop the combination steroid-antifungal cream, screen household contacts and close contacts, and advise the school to examine symptomatic students. Tinea is not notifiable in India. Mass prophylaxis is not evidence-based.
Tinea corporis is contagious and spreads through contact. The public-health action is contact tracing (household members and close contacts) and screening. Topical steroid-antifungal combination cream misuse must be stopped. Tinea is not a notifiable disease in India. Mass prophylactic antifungal treatment of contacts without examination is not recommended.
The most important public-health action is contact tracing: screen household and close contacts for tinea, stop the steroid combination cream, and advise the school to examine symptomatic contacts. Tinea is NOT notifiable in India. Wood's lamp is negative for this organism (Trichophyton). Mass prophylaxis is not indicated.
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A 40-year-old immunocompetent male presents with severely thickened, hyperkeratotic, crumbling nails on ALL twenty nails (finger and toenails) with hyperkeratotic skin on the palms and soles. He has never been treated. KOH is positive for septate hyphae. Which dermatophyte infection syndrome is this, and why does it affect all twenty nails?
Correct. T. rubrum chronic widespread infection can involve all twenty nails along with plantar/palmar hyperkeratosis. This 'two feet two hands' TFTHN pattern is characteristic of T. rubrum chronic infection. KOH confirming septate hyphae distinguishes this from nail psoriasis. Treatment: prolonged oral terbinafine or itraconazole.
Trichophyton rubrum is the commonest dermatophyte causing chronic widespread infection. The 'two feet, two hands' (TFTHN = tinea pedis + manuum) pattern with all twenty nail involvement is a recognised syndrome of T. rubrum. The KOH confirms fungal aetiology, distinguishing it from nail psoriasis. Management requires prolonged systemic antifungal therapy.
The correct answer is the 'two feet two hands' T. rubrum syndrome. Chronic mucocutaneous candidiasis involves Candida (pseudohyphae on KOH) and is associated with immunodeficiency. KOH showing septate hyphae confirms dermatophyte, not Candida. Nail psoriasis would not show fungal elements on KOH.
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You are about to perform a KOH mount on scale from a lesion you suspect is tinea cruris. You have 20% KOH available, a spirit lamp, a glass slide, cover slip, and a bright-field microscope. After placing the scale on the slide and adding a drop of KOH, what is the CORRECT next step before covering with the cover slip?
Correct. Gentle warming (2-3 passes over spirit lamp) accelerates KOH clearing. Boiling destroys hyphae. Room temperature clearing takes 15-20 minutes but is acceptable. India ink is used for Cryptococcus capsule detection in CSF, not for KOH mounts.
After adding KOH to the skin scraping, gently warm the slide by passing it 2-3 times over the spirit lamp flame (do not boil). This accelerates KOH clearing of keratin without destroying fungal hyphae. The preparation can also clear at room temperature over 15-20 minutes if heating is not desired. India ink is used for Cryptococcus capsule detection, not routine KOH.
The correct technique is gentle warming over the spirit lamp (2-3 passes) to accelerate KOH clearing without boiling or destroying hyphae. Boiling destroys fungal elements. India ink is for Cryptococcus detection in CSF. Waiting 24 hours is acceptable but unnecessarily slow.
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A 35-year-old female with well-controlled type 2 diabetes presents with white plaques on the oral mucosa that wipe off easily, leaving a raw bleeding surface, plus a satellite-pustule-containing rash in the axillary folds with maceration. Her blood sugar today is 8.2 mmol/L. KOH from both sites confirms Candida. Which statement about her management is MOST accurate?
Correct. Simultaneous antifungal therapy (topical for skin/mucosal disease; systemic if extensive) AND glycaemic optimisation is the complete management. Hyperglycaemia creates an environment favouring Candida overgrowth by impairing neutrophil function and providing excess glucose substrate. Treating only the fungus without addressing the host factor leads to recurrence.
Candidiasis in diabetics is driven by both fungal load and host immune deficiency from hyperglycaemia. Management must address both: antifungal therapy for active infection AND glycaemic optimisation to restore host defences and prevent recurrence. Neither alone is sufficient for durable cure.
Both antifungal treatment AND glycaemic optimisation are required. Treating fungus alone without correcting hyperglycaemia leads to recurrence (hyperglycaemia impairs neutrophil fungicidal activity and provides substrate for Candida). Glycaemic control alone will not cure active candidiasis fast enough. A single oral fluconazole dose is insufficient for both sites.
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A dermatology registrar is counselling a 25-year-old male with extensive tinea corporis about treatment. The patient has already used two courses of topical clotrimazole (each 4 weeks) without improvement. KOH confirms septate hyphae. In the current Indian epidemiological context, which statement BEST guides the choice of systemic antifungal?
Correct. The epidemic of terbinafine-resistant T. indotineae in India means that empiric terbinafine for recalcitrant or extensive tinea is no longer the safest choice. Itraconazole 200 mg/day for 4–8 weeks (with food, as bioavailability is enhanced by food) is the preferred systemic agent in the current context. Always counsel about stopping steroid combination creams.
India has an epidemic of terbinafine-resistant T. indotineae. Recalcitrant tinea unresponsive to topical therapy, especially in the current Indian context, should be treated empirically with itraconazole rather than terbinafine when systemic therapy is needed. Fluconazole has lower efficacy than terbinafine or itraconazole for tinea. Culture-sensitivity is ideal but impractical in routine practice.
In India's current epidemiological context, terbinafine resistance (T. indotineae) has made itraconazole the preferred systemic antifungal for recalcitrant/extensive tinea. Fluconazole has limited efficacy for dermatophytes. Culture and sensitivity is ideal but not routine practice. Option B correctly applies current Indian clinical guidelines.
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