Derm Cases · Dermatology / Paediatrics / Genodermatoses
OSCE — collodion baby and ichthyosis spectrum: IV vs XLI vs ARCI
An 8-minute OSCE on distinguishing ichthyosis vulgaris, X-linked ichthyosis and congenital ichthyoses, collodion/harlequin neonatal care, and when acquired ichthyosis signals systemic disease.
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Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE on distinguishing ichthyosis vulgaris, X-linked ichthyosis and congenital ichthyoses, collodion/harlequin neonatal care, and when acquired ichthyosis signals systemic disease.
Brief (to candidate)
A neonate is born encased in a tight shiny membrane with ectropion. Separately, a clinic has (A) a child with fine white extensor scale and palmar hyperlinearity and (B) a boy with large dark scales including flexures. You have 8 minutes to classify ichthyoses, manage the collodion baby, and name red-flag associations.
[9]Candidate instructions
- Classify ichthyosis vulgaris (FLG), X-linked ichthyosis (STS), and ARCI / harlequin clinically and genetically.
- Outline collodion baby / harlequin NICU care and role of systemic retinoids.
- State XLI extracutaneous associations (cornea, cryptorchidism, contiguous gene).
- Name when acquired ichthyosis prompts malignancy work-up.
- Give adult/child emollient–keratolytic principles for common IV.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| IV recognition | Fine white scale, extensors, flexures spared, palmar hyperlinearity, strong atopic dermatitis link; filaggrin (FLG) semidominant inheritance[2][3] |
| XLI recognition | Male; larger dark-brown scales, often involving flexures; STS / Xp22.3; comma-shaped corneal opacities, cryptorchidism; consider Kallmann contiguous deletion[6][1] |
| Collodion / harlequin | Humidity-controlled incubator, infection control, nutrition, eye care; harlequin (ABCA12) armour plates — early systemic retinoid (e.g. acitretin/isotretinoin pathway under specialist) improves survival; collodion membrane may evolve to lamellar/CIE phenotypes (e.g. TGM1)[7][8][1] |
| Netherton / EI notes | Netherton (SPINK5/LEKTI): ichthyosis linearis circumflexa, bamboo hair, allergy; epidermolytic ichthyosis KRT1/KRT10 blistering at birth then hyperkeratosis |
| Acquired ichthyosis | New adult-onset ichthyosiform scaling → screen for Hodgkin lymphoma, drugs, malnutrition, hypothyroidism — not primary genetic disease alone[5] |
| Chronic management | Emollients (urea/lactic acid where tolerated), avoid excess irritants; genetic counselling; specialist for syndromic/congenital forms |
| Communication | Prognosis differs dramatically IV (benign) vs harlequin/JEB-like severity spectrum; family counselling |
Model key actions
- Separate IV (FLG, flexure-sparing) from XLI (STS, male, dark scales + extracutaneous).[2][6]
- Treat collodion/harlequin as NICU dermatology emergency; early retinoid pathway for harlequin under specialist care.[7][8]
- Investigate acquired adult ichthyosis for systemic disease including lymphoma.[5]
Common errors
- Calling all scale “eczema” without ichthyosis differential.
- Missing XLI corneal opacities / cryptorchidism / contiguous gene risk.
- Discharging collodion baby without NICU humidity/infection plan.
- Ignoring acquired ichthyosis as a paraneoplastic clue.
References8ShowHide
- [1]Gutiérrez-Cerrajero C, Sprecher E, Paller AS, et al. Ichthyosis. Nat Rev Dis Primers, 2023.PMID 36658199
- [2]Jaffar H, Shakir Z, Kumar G, et al. Ichthyosis vulgaris: An updated review. J Eur Acad Dermatol Venereol, 2023.PMID 36751330
- [3]Takeichi T, Akiyama M. Inherited ichthyosis: Non-syndromic forms. J Dermatol, 2016.PMID 26945532
- [6]Hazan C, Orlow SJ, Schaffer JV X-linked recessive ichthyosis. Int J Dermatol, 2005.PMID 16403384
- [7]Tsivilika M, Kavvadas D, Karachrysafi S, et al. Management of Harlequin Ichthyosis: A Brief Review of the Recent Literature. Cureus, 2022.PMID 35740830
- [8]Perumal VK, Baalann KP Collodion baby. StatPearls, 2021.PMID 34804344
- [5]Haber R, Feghali J, Nadir U, et al. Acquired ichthyosis: a clinical review. Int J Dermatol, 2023.PMID 37422878
- [9]Tsivilika M, Kavvadas D, Karachrysafi S, et al. Management of Harlequin Ichthyosis: A Brief Review of the Recent Literature Children (Basel), 2022.PMID 35740830