Derm Cases · Dermatology / Infectious Diseases / Primary Care
OSCE — annular scaly plaque: tinea corporis diagnosis and treatment
An 8-minute OSCE station on ringworm recognition, KOH confirmation, topical versus systemic antifungal regimens with doses, tinea incognito and Majocchi red flags, reservoirs, and Trichophyton indotineae resistance awareness.
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Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on ringworm recognition, KOH confirmation, topical versus systemic antifungal regimens with doses, tinea incognito and Majocchi red flags, reservoirs, and Trichophyton indotineae resistance awareness.
Brief (to candidate)
A 22-year-old student has a slowly expanding itchy annular plaque on the trunk for 3 weeks after sharing gym mats. The border is raised and scaly with central clearing; he previously used a potent topical steroid which temporarily flattened the edge. You have 8 minutes to diagnose, confirm, treat, and prevent recurrence.
Candidate instructions
- Recognise tinea corporis and name common dermatophytes.
- Plan bedside confirmation (KOH ± culture).
- Prescribe first-line topical therapy with application technique and duration.
- State indications for systemic therapy with doses.
- Identify tinea incognito, Majocchi granuloma, and resistance concerns.
- Address reservoirs (pedis/unguium, contacts) and advice.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Recognition | Annular scaly plaque with active raised edge and central clearing = tinea corporis (ringworm); Trichophyton, Microsporum, Epidermophyton[1][3] |
| Diagnosis | KOH microscopy of scale from active edge; culture/species ID if refractory, outbreak, or systemic Rx planned |
| Topical first-line | Terbinafine 1% cream BD × 1–2 weeks (preferred, fungicidal) or azole (clotrimazole 1% BD × 2–4 weeks); apply 2 cm beyond edge; continue 1–2 weeks after clinical clearance; avoid steroid–antifungal combinations as routine first-line[2][4] |
| Systemic Rx | Extensive, multiple sites, follicular/Majocchi, immunocompromise, failed topical: terbinafine 250 mg OD × 2–4 weeks (or itraconazole pulse/course); check interactions/LFTs if prolonged |
| Red flags | Tinea incognito after topical steroid — stop steroid, confirm fungus; Majocchi granuloma (follicular papules/pustules) needs systemic Rx; extensive refractory disease → consider T. indotineae (SQLE resistance) → itraconazole-based strategies + culture |
| Reservoirs | Examine feet and nails; treat concurrent tinea pedis/unguium; avoid shared towels/mats; screen household/pets if zoophilic suspected |
| Communication | Explain contagion and hygiene; return if spreading despite adherence or deep follicular nodules |
Model key actions
- Diagnose tinea corporis (steroid-modified → tinea incognito risk); confirm with KOH.[1][3]
- Terbinafine 1% BD × 1–2 weeks for localised disease; systemic terbinafine if extensive/follicular.[2][4]
- Stop unsupervised potent steroids on annular plaques; treat foot reservoir.
Common errors
- Treating with topical steroid alone.
- Stopping antifungal as soon as itch improves (incomplete edge clearance).
- Using topical only for Majocchi / extensive disease.
- Ignoring tinea pedis/nails as the source of recurrence.
- Missing emerging terbinafine-resistant extensive tinea in high-prevalence settings.
References4ShowHide
- [1]Leung AK, Lam JM, Leong KF, et al. Tinea corporis: an updated review. Drugs in Context, 2020.PMID 32742295
- [2]Sahoo AK, Mahajan R. Management of tinea corporis, tinea cruris, and tinea pedis: A comprehensive review. Indian dermatology online journal, 2016.PMID 27057486
- [3]Ely JW, Rosenfeld S, Seabury Stone M. Diagnosis and management of tinea infections. American Family Physician, 2014.PMID 25403034
- [4]Barac A, Stjepanovic M, Krajisnik S, et al. Dermatophytes: Update on Clinical Epidemiology and Treatment. Mycopathologia, 2024.PMID 39567411