Derm Cases · Dermatology / General Medicine / Obstetrics interface
OSCE — assessment of pityriasis rosea with herald patch and pregnancy counselling
An 8-minute OSCE station on recognition of herald patch and Christmas-tree distribution, HHV-6/7 association, exclusion of secondary syphilis and other mimics, supportive management, and pregnancy risk counselling for early-onset extensive pityriasis rosea.
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Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on recognition of herald patch and Christmas-tree distribution, HHV-6/7 association, exclusion of secondary syphilis and other mimics, supportive management, and pregnancy risk counselling for early-onset extensive pityriasis rosea.
Brief (to candidate)
A 24-year-old woman noticed a single oval scaly plaque on the trunk 10 days ago, followed by a widespread rash of smaller oval plaques oriented along skin cleavage lines on the back. Mild itch; no drug history. She is 8 weeks pregnant. You have 8 minutes to diagnose, exclude serious mimics, manage supportively, and counsel regarding pregnancy.
Candidate instructions
- Elicit herald patch history and describe the secondary eruption pattern.
- Apply diagnostic criteria language and list key differentials (especially secondary syphilis).
- Link to proposed HHV-6/HHV-7 association without overclaiming causality at the bedside.
- Outline supportive management and when to treat more actively.
- Counsel on pregnancy risk for early gestational, extensive PR and disposition.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Recognition | Herald patch (larger precursor plaque) → days later secondary eruption of oval plaques with collarette scale along Langer lines (Christmas-tree pattern on back)[1][4] |
| Aetiology framing | Discusses possible HHV-6/HHV-7 reactivation association; self-limited viral-associated exanthem concept rather than contagious bacterial infection[2] |
| Differential / red flags | Must exclude secondary syphilis (palmoplantar involvement, mucous patches, lymphadenopathy, sexual history → VDRL/RPR when indicated); also guttate psoriasis, tinea corporis, drug eruption, nummular eczema |
| Natural history | Self-limiting over ~6–8 weeks (range weeks–months); mild pruritus common; systemic symptoms usually mild if present |
| Management | Reassurance + emollients; antihistamine/low-potency topical steroid for itch; UV/phototherapy or other actives only if severe and appropriate; avoid unnecessary systemic antibiotics[5] |
| Pregnancy counselling | Early pregnancy (esp. first trimester) + extensive/long-lasting PR associated in literature with adverse pregnancy outcomes risk signal — obstetric liaison, close follow-up, avoid experimental systemic therapy without specialist input[7] |
| Communication | Explains non-scarring course; safety-net if lesions become purulent, mucous membranes involved, or pregnancy warning symptoms |
Model key actions
- Diagnose classic pityriasis rosea (herald patch → Christmas-tree secondary rash).[1][4]
- Serology for syphilis if any diagnostic doubt or risk factors.
- Supportive care for mild disease; pregnancy risk discussion and obstetric review for first-trimester extensive PR.[5][7]
Common errors
- Missing the herald patch history.
- Failing to consider secondary syphilis.
- Treating routinely with prolonged systemic antibiotics or antifungal without indication.
- Reassuring a pregnant patient with extensive early-onset PR without obstetric risk discussion.
- Overstating HHV testing as mandatory in typical self-limited cases.
References5ShowHide
- [1]Drago F, Broccolo F, Rebora A, et al. Pityriasis Rosea: A Comprehensive Classification. Dermatology (Basel, Switzerland), 2016.PMID 27096928
- [2]Drago F, Broccolo F, Rebora A. Pityriasis rosea: an update with a critical appraisal of its possible herpesviral etiology. Journal of the American Academy of Dermatology, 2009.PMID 19615540
- [4]Chuh AA. Diagnostic criteria for pityriasis rosea: a prospective case control study for assessment of validity. Journal of the European Academy of Dermatology and Venereology, 2003.PMID 12602987
- [5]Chuh A, Zawar V, Sciallis G, et al. A position statement on the management of patients with pityriasis rosea. Journal of the European Academy of Dermatology and Venereology, 2016.PMID 27406919
- [7]Drago F, Broccolo F, Zaccaria E, et al. Pregnancy outcome in patients with pityriasis rosea. Journal of the American Academy of Dermatology, 2008.PMID 18489054