Definition
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Tinea infections (dermatophytoses): superficial fungal infections caused by Trichophyton, Microsporum, and Epidermophyton species.
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Classified by body site:
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Tinea capitis – scalp
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Tinea corporis – body (excluding scalp, groin, feet, nails)
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Tinea cruris – groin (“jock itch”)
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Epidemiology & Risk Factors
| Type | Age/Population | Risk Factors |
|---|---|---|
| Tinea capitis | Children 3–7 years | Crowded settings, poor hygiene, close contact, African descent at higher risk |
| Tinea corporis | All ages | Warm, humid climate, contact with infected person or animal |
| Tinea cruris | Adults, mostly males | Obesity, sweating, tight clothing, diabetes, immunosuppression |
Clinical Features
| Feature | Tinea Capitis | Tinea Corporis | Tinea Cruris |
|---|---|---|---|
| Lesion | Scaly patches, alopecia, broken hairs, black dots; may have pustules (kerion) | Ring-shaped, erythematous, scaly plaques with central clearing | Erythematous, sharply demarcated plaques in groin/flexures, usually sparing scrotum |
| Symptoms | Pruritus, sometimes tender swelling | Itching | Itching, burning |
| Complications | Secondary bacterial infection, kerion formation | Rare | Secondary bacterial infection, chronicity if untreated |
💡 PLAB Tip: Ringworm lesions with central clearing and raised border are classic.
Differential Diagnosis
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Seborrheic dermatitis: especially scalp; greasy scales, no alopecia in patchy hair loss
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Eczema: ill-defined borders, no ring pattern
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Psoriasis: silvery plaques, often extensor surfaces, nails involved
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Candidiasis (for groin): more moist, satellite pustules, often involves scrotum
Investigations
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Clinical diagnosis often sufficient
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KOH (potassium hydroxide) mount → shows hyphae
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Fungal culture → rarely needed, for resistant cases or epidemiology
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Wood’s lamp: useful for some Microsporum infections (fluoresces green)
Management
Tinea Capitis
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Oral antifungal therapy required:
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Griseofulvin (first-line in children)
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Terbinafine (alternative, especially in older children/adults)
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Adjunct: antifungal shampoo (ketoconazole, selenium sulfide) to reduce transmission
Tinea Corporis & Cruris
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Topical antifungal therapy first-line:
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Terbinafine cream 1% for 1–2 weeks
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Clotrimazole or miconazole alternative
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Oral therapy only for extensive or refractory cases
General Measures
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Keep affected areas dry
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Avoid sharing towels, clothing, hats, or hairbrushes
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Treat pets if zoonotic source suspected
Complications
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Secondary bacterial infection
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Chronic or recurrent infections if untreated or in immunocompromised patients
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Scarring alopecia in severe tinea capitis
PLAB-Style Questions
Q1: A 6-year-old child presents with scaly, circular patch on the scalp with broken hairs and mild alopecia. What is the first-line treatment?
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A. Topical clotrimazole
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B. Oral griseofulvin
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C. Topical corticosteroid
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D. Oral fluconazole
✅ Answer: B. Oral griseofulvin
(Tinea capitis requires systemic therapy for hair involvement.)
Q2: A 25-year-old man presents with itchy, erythematous, ring-shaped plaques with central clearing on his groin. Which topical therapy is most appropriate?
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A. Topical steroid
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B. Terbinafine cream
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C. Topical mupirocin
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D. Oral flucloxacillin
✅ Answer: B. Terbinafine cream
(Tinea cruris responds well to topical antifungals.)
High-Yield Pearls
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Tinea capitis = children, oral antifungal required; kerion = inflammatory variant
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Tinea corporis/cruris = adults, topical therapy usually sufficient
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Central clearing with raised borders = hallmark lesion
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Keep areas dry and avoid sharing personal items
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PLAB Tip: Tinea capitis with hair loss in a child = systemic therapy; Tinea corporis/cruris in adult = topical therapy
