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DR7.1-2 | Fungal Infections — PBL Case

CLINICAL SETTING

You are a final-year medical student posted at the skin OPD of a district hospital in Maharashtra. It is a busy Monday morning. The first patient to enter is Sunita, a 28-year-old homemaker and mother of two children (ages 6 and 9). She is accompanied by her husband Prakash, a 35-year-old construction worker. Both are visibly distressed. Sunita says through the interpreter: 'Doctor, this rash started near my waist two months ago. The pharmacy gave me a cream that helped for a few days, but then it came back worse. Now my husband has it too, and the children are starting to get spots on their chests. We have been trying cream after cream and spending money we don't have. Nothing is working.' On examination of Sunita: extensive hyperpigmented plaques with a polycyclic, ill-defined border involving the waist, groin, inner thighs, and lower abdomen. Marked hyperpigmentation throughout. No central clearing. No satellite pustules. Wood's lamp examination is negative. On examining Prakash: similar lesions involving the groin and inner thighs, plus one annular plaque with central clearing on the right forearm. The children have small, annular plaques with raised erythematous borders on the trunk. The pharmacy bags Sunita brings in contain: (1) a cream labelled 'clotrimazole + betamethasone' and (2) a cream labelled 'miconazole + clobetasol'. Both were bought without prescription.

Trigger 1: Trigger 1 — Recognising the Pattern and Planning Investigation

The consultant asks you to examine Sunita's lesions first. You notice: extensive polycyclic plaques with hyperpigmentation and ill-defined borders, no central clearing despite 2 months of 'treatment,' Wood's lamp negative. You decide to perform a KOH mount. Sunita asks: 'Doctor, why are you doing this extra test? Can't you just give me a cream that works?'

DISCUSSION POINTS

  • What clinical features in Sunita's presentation suggest a fungal infection, and which features have been altered by the creams she has been using? How does topical betamethasone change the classic morphology of tinea?
  • Describe step-by-step how you would perform a KOH mount on Sunita's lesion: where on the lesion would you scrape, why, and what technique errors must you avoid? What finding would confirm a dermatophyte infection vs Candida vs Malassezia?
  • How would you explain the need for the KOH mount to Sunita in terms she can understand, without dismissing her frustration about repeated treatments that have failed?
Click to reveal Trigger 2: Trigger 2 — KOH Result and Diagnosis (discuss previous trigger first!)

Trigger 2: Trigger 2 — KOH Result and Diagnosis

You examine the KOH preparation under the microscope. At 40× magnification you observe: long, branching, septate hyphae traversing multiple keratinocytes. You also see some refractile straight lines forming a geometric grid pattern. You distinguish the true hyphae from the artefact and report a positive KOH for dermatophytes. Fungal culture is sent and later returns Trichophyton indotineae. The consultant tells you: 'This is the fifth case of T. indotineae this week. Look at those creams she's been using — that's the whole problem.'

DISCUSSION POINTS

  • What is Trichophyton indotineae and why is it clinically significant in the current Indian context? How does its terbinafine resistance arise (mechanism at the molecular level), and what are the implications for treatment?
  • In the KOH preparation, you saw refractile grid-like lines alongside true hyphae. What is this artefact called, and what specific feature distinguishes it from genuine fungal hyphae? Why does it occur?
  • Construct the complete differential diagnosis for Sunita's presentation (at least 4 conditions), and explain for each how you would use clinical features, KOH, and other investigations to confirm or exclude it.
Click to reveal Trigger 3: Trigger 3 — Management and the Family Cluster (discuss previous trigger first!)

Trigger 3: Trigger 3 — Management and the Family Cluster

The consultant turns to the family: Sunita (extensive tinea cruris/corporis, T. indotineae confirmed), Prakash (tinea cruris + isolated tinea corporis, milder), the 6-year-old (2 annular plaques on trunk), the 9-year-old (3 annular plaques on trunk + one patch of broken hair on scalp). The consultant says: 'This is a household cluster. Think about each person separately and together. And decide what to do about those creams right now.'

DISCUSSION POINTS

  • Design a complete management plan for each family member: (a) Sunita — systemic vs topical, drug of choice given T. indotineae, dose, duration; (b) Prakash — same decision framework; (c) the 6-year-old — appropriate paediatric antifungal for tinea corporis; (d) the 9-year-old — additional management required for the scalp lesion and why topical therapy alone is insufficient for tinea capitis.
  • Prakash asks: 'Doctor, why are you prescribing different medicines from what the pharmacy gave us? Those are expensive and we don't have insurance.' How would you explain: (a) why the combination creams must be discarded immediately; (b) why the new prescription (itraconazole) is necessary despite its cost; (c) what the likely consequences are of continuing the combination creams?
  • What hygiene and household measures would you recommend to prevent re-infection between family members? Specify practical steps appropriate for a working-class family sharing one bathroom and limited laundry facilities.
Click to reveal Trigger 4: Trigger 4 — The Bigger Picture: An Epidemic at the PHC Level (discuss previous trigger first!)

Trigger 4: Trigger 4 — The Bigger Picture: An Epidemic at the PHC Level

After the family leaves, the consultant shares the OPD register: in the past 3 months, 68 patients have presented with recalcitrant tinea at this OPD. Almost all had used topical steroid-antifungal combinations. The Medical Officer of Health asks you, as a visiting student, to draft a brief 'action note' for the district's primary health centres.

DISCUSSION POINTS

  • Analyse the epidemiological and pharmaceutical drivers behind India's epidemic of recalcitrant tinea and T. indotineae. What role do (a) OTC availability of potent topical corticosteroids; (b) pharmacist prescribing practices; and (c) pharmaceutical marketing play in perpetuating this cycle?
  • Propose three concrete, feasible interventions at the PHC level that could reduce the burden of recalcitrant tinea in the district. For each intervention, specify the target (patient, prescriber, pharmacist, or regulator), the action, and the expected outcome.
  • Reflecting on this family's experience: what systemic failures in health service delivery allowed this household cluster to develop over 2 months of treatment-seeking without receiving a correct diagnosis or appropriate therapy? What individual and system-level changes could prevent this?