Derm Cases · Dermatology / Paediatrics / Neurocutaneous
OSCE — Blaschkoid neonatal vesicles: incontinentia pigmenti staging and eye urgency
An 8-minute OSCE on IP (IKBKG/NEMO) four cutaneous stages, male lethality, eosinophilic histology, and urgent ophthalmology for retinal vasculopathy.
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Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE on IP (IKBKG/NEMO) four cutaneous stages, male lethality, eosinophilic histology, and urgent ophthalmology for retinal vasculopathy.
Brief (to candidate)
A newborn girl has linear Blaschkoid vesicles on a limb with peripheral eosinophilia. Mother has swirled hyperpigmentation. You have 8 minutes to diagnose IP stages, plan investigations, and prioritise ophthalmology and genetic counselling.
Candidate instructions
- State inheritance (X-linked dominant IKBKG/NEMO) and why males usually die in utero.
- List the four cutaneous stages along Blaschko lines.
- Plan biopsy / genetics and extracutaneous survey (teeth, eyes, CNS, hair, nails).
- Prioritise urgent ophthalmology for retinal ischaemia/detachment risk.
- Counsel transmission risk and family screening.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Genetics | IKBKG (NEMO) Xq28; X-linked dominant; usually lethal in males; almost exclusively females (or rare XXY/mosaic males)[1][5] |
| Four stages | I vesicular/bullous → II verrucous → III hyperpigmented (whorled) → IV hypopigmented/atrophic Blaschkoid; stages may overlap[2][4] |
| Diagnosis | Clinical + eosinophilic spongiosis on biopsy of stage I; genetic confirmation common exon 4–10 deletion; peripheral eosinophilia supportive[1] |
| Eye urgency | Retinal vasculopathy/ischaemia can progress to detachment — urgent ophthalmology even if “asymptomatic”; early laser can prevent vision loss[3] |
| Other systems | Dental anomalies (~most common extracutaneous), seizures/developmental issues, alopecia, nail dystrophy — neurology if seizures/delay |
| Differential | Not bullous impetigo alone; not ordinary HSV without pattern; distinguish from other Blaschkoid genodermatoses |
| Counselling | Mother often mildly affected; 50% transmission risk to offspring; prenatal genetics discussion |
Model key actions
- Diagnose IP in a female neonate with Blaschkoid vesicles + eosinophilia and stage the eruption.[1][2]
- Refer same-pathway ophthalmology for retinal screening.[3]
- Confirm NEMO genetics and counsel X-linked dominant inheritance.[5]
Common errors
- Treating only as infection without Blaschko-line recognition.
- Delaying eye exam until visual symptoms appear.
- Assuming affected boys are common without mosaicism/XXY explanation.
- Missing dental/CNS surveillance planning.
References5ShowHide
- [1]Rosser T. Incontinentia pigmenti. Semin Pediatr Neurol, 2024.PMID 39389657
- [2]Cammarata-Scalisi F, Fusco F, Ursini MV Incontinentia Pigmenti. Orphanet J Rare Dis / review, 2019.PMID 30660327
- [3]Islam YFK, Khurshid SG Incontinentia pigmenti and the eye. Surv Ophthalmol, 2022.PMID 35819905
- [4]Poziomczyk CS, Recuero JK, Bringhenti L, et al. Incontinentia pigmenti. Clin Genet, 2014.PMID 24626645
- [5]Scheuerle AE, Ursini MV. Incontinentia Pigmenti. GeneReviews, 1993.PMID 20301645