Dermatology & Medical Genetics & Pediatrics & Family Medicine
Ichthyosis
Ichthyoses are a heterogeneous group of genodermatoses (skin diseases of genetic origin) or, more rarely, acquired dermatoses, characterized by an abnormality in keratinization leading to excessive and persistent scaling of the skin, resembling fish scales – hence their name derived from the Greek «ichthys» (fish). They result from mutations in genes involved in keratinocyte differentiation, the formation of the lipid skin barrier, or the proteolysis of corneodesmosins that allows for physiological scaling. The modern classification of ichthyoses, proposed by the First Ichthyosis Consensus Conference (Oji 2010 – Journal of the American Academy of Dermatology), distinguishes between common ichthyoses (non-syndromic, isolated) – the most frequent of which is autosomal dominant ichthyosis vulgaris – and autosomal recessive congenital ichthyoses (ARCIs) and syndromic forms where ichthyosis is accompanied by extracutaneous involvement. Ichthyosis vulgaris, caused by loss-of-function mutations in the FLG gene encoding filaggrin, is by far the most common with a prevalence of 1/250 to 1/1,000 depending on the population, and constitutes the main genetic risk factor for atopic dermatitis. Severe forms – lamellar ichthyosis, bullous or non-bullous congenital ichthyosiform erythroderma – are much rarer (1/100,000 to 1/300,000 births) and often present at birth as collodion babies (covered by a tight, parchment-like membrane). Treatment is essentially symptomatic – based on emollients, keratolytics, and retinoids – as no curative therapy is available for most genetic forms.
Classification, genetics, and pathophysiology
- Modern classification of ichthyoses and genetic basis: Common ichthyoses (non-syndromic — common): autosomal dominant ichthyosis vulgaris (IV-AD): FLG gene (filaggrin) — chromosome 1q21.3 → loss-of-function mutations (R501X + 2282del4 — the most common in Northern Europe) → prevalence: 1/250 to 1/1,000 → autosomal dominant → filaggrin = key structural protein of the stratum corneum + source of natural moisturizing factors (NMF — Natural Moisturizing Factors) → FLG mutations → barrier defect + altered skin pH → dry skin + fine, scaly flakes + follicular keratosis + mild palmar-plantar involvement + very strong association with atopic dermatitis (Palmer 2006 — Nature Genetics: FLG mutations = primary genetic factor in atopic dermatitis) + no skin involvement at birth → onset in childhood + improvement in adulthood + improvement in warm, humid climates + worsening in winter → X-linked recessive ichthyosis (XLI): STS gene (steroid sulfatase) — Xp22.3 chromosome → deletion or mutation → steroid sulfatase enzyme deficiency → accumulation of cholesterol sulfate in the skin → desquamation disorder → prevalence: 1 in 2,000 to 1 in 6,000 males → affected hemizygotes + female carriers often minimally or not affected → clinical features: large, grayish-brown scales, primarily on the trunk, limbs, and neck; face, palms, and soles spared; persists into adulthood (no improvement with age); onset at birth or within the first few weeks; punctate corneal opacities (in adults — asymptomatic) + cryptorchidism (10–20% of boys) + risk of delayed delivery (cholesterol sulfate inhibits the cervical keratin matrix) → diagnosis: lipoprotein electrophoresis (accumulation of cholesterol sulfate) + STS gene deletion by FISH or CGH array → autosomal recessive congenital ichthyoses (ARCI): several subtypes depending on the mutated gene: ABCA12 (Harlequin baby + severe lamellar ichthyosis) + TGM1 (transglutaminase 1 — lamellar ichthyosis + ichthyosiform erythroderma) + ALOX12B + ALOXE3 (lipoxygenases) + CYP4F22 + NIPAL4 + PNPLA1 + CERS3 + collodion baby: presentation at birth → infant wrapped in a collodion membrane (tight, parchment-like film + yellowish-brown) → ectropion + eclabium (eversion of the eyelids + lips) → acrocyanosis + hyperthermia → the membrane peels off within a few weeks → variable course depending on the gene: toward lamellar ichthyosis or ichthyosiform erythroderma, or toward near-normal skin (self-healing collodion — resolving baby-collodion) → Harlequin baby (harlequin ichthyosis): most severe form + ABCA12 gene → abnormal lipid transport in lamellar granules → enormous scales + keratosis in hexagonal plaques + massive ectropion and eclabium → improved prognosis with early treatment with retinoids (acitretin) → Rajpopat 2011 — Pediatrics: survival into adulthood possible with intensive treatment; syndromic ichthyoses: Netherton syndrome (SPINK5 — LEKTI) + Sjögren-Larsson syndrome (ALDH3A2 — fatty aldehyde dehydrogenase deficiency → neurospasticity + mental retardation + ichthyosis) + Chanarin-Dorfman syndrome (ABHD5 — triglyceride accumulation) + Refsum syndrome (PAHX — phytanoyl-CoA hydroxylase → phytanic acid accumulation → neuropathy + ichthyosis + retinitis pigmentosa + ataxia) + KID syndrome (GJB2 — connexin 26 → keratitis + ichthyosis + deafness) → acquired ichthyoses: associated with systemic conditions: Hodgkin’s lymphoma + sarcoidosis + hypothyroidism + lupus + dermatomyositis + medications (nicotinic acid + butyrate + clofazimine) → histologically identical to hereditary forms but occurring in adults → systemic evaluation if acquired ichthyosis of adulthood
- Pathophysiology — Skin Barrier and Molecular Mechanisms: Normal structure of the skin barrier: epidermis composed of 4–5 layers → basal layer (dividing keratinocytes) → spinous layer → granular layer → stratum corneum (nucleus-free corneocytes in a lipid matrix) → physiological desquamation: kallikreins (KLK5 + KLK7) → degrade corneodesmosins → release of corneocytes → desquamation → the lipid barrier (ceramides + free fatty acids + cholesterol) = 50% of the stratum corneum’s content → ensures water retention → NMF (Natural Moisturizing Factor) = product of filaggrin degradation → composed of hygroscopic amino acids (PCA + glutamate + glycine + citrulline + urea) → maintains hydration of the stratum corneum → filaggrin defect (FLG mutations) → reduced NMF → dry skin + high skin pH → activation of kallikreins → hyperdesquamation + barrier defect → entry of allergens → sensitization → atopic dermatitis; mechanisms of ichthyosis depending on the affected pathway: filaggrin (FLG) defect → atopic dermatitis-associated ichthyosis (AD) → no granule atrophy → normal lamellar granules → abnormal water and NMF retention + transglutaminase 1 (TGM1) → lamellar ichthyosis → lack of cross-linking of stratum corneum proteins → fragile stratum corneum → impaired corneocyte cohesion → thick, flat scales → lipid transport defect (ABCA12) → Harlequin ichthyosis → lack of lipid secretion in lamellar granules → absent lipid barrier → massive hyperpermeability + 12R-lipoxygenase deficiency / ALOXE3 → lamellar ichthyoses → abnormal lipids in the stratum corneum → scales → steroid sulfatase deficiency (STS) → X-linked ichthyosis → accumulation of cholesterol sulfate → inhibition of kallikreins → impaired desquamation → thick scales → LEKTI deficiency (kallikrein inhibitor — SPINK5) → Netherton syndrome → excessive kallikrein activity → hyperdesquamation + severe inflammation + allergic sensitization (very high IgE levels + severe atopy)
Clinical presentation, diagnosis, and management
| Type / domain | Data, criteria and procedures | Key studies and recommendations |
|---|---|---|
| Clinical presentation and differential diagnosis Ichthyosis vulgaris — XLI — ICCAR — collodion baby — Harlequin baby — ectropion — pruritus — histology — skin biopsy — genotyping |
Ichthyosis vulgaris AD — clinical presentation: onset in early infancy (3–12 months) → fine, scaly, white or grayish scales → characteristic distribution: extensor surfaces of the limbs (anterior surfaces of the legs ++) + trunk + back + sparing of major skin folds + palms + soles (unlike XLI) + follicular keratosis: perifollicular keratotic papules on the arms + thighs + buttocks → atrophy of the palmar papillary lines + Association with atopic dermatitis (50–60% of patients with ichthyosis vulgaris) + asthma + allergic rhinitis + diagnosis is clinical → confirmation: FLG genotyping if necessary (genetic counseling) → histology not essential but would show: absent or severely reduced granular layer (hypo- or agranulosis — in contrast to the normal or hypertrophied granular layer seen in other forms of ichthyosis) + compact, orthokeratotic stratum corneum; X-linked recessive ichthyosis (XLI) — clinical presentation: large + thick + brownish-black or grayish-green scales + covering the trunk + neck + limbs + often the scalp + present from birth or the first few weeks + persisting throughout life (no improvement with age or heat) + partial sparing of the face + palms and soles often affected (unlike ichthyosis vulgaris) + punctate corneal opacities in adults (asymptomatic — slit-lamp examination) + cryptorchidism in 10–20% of cases + diagnosis: clinical presentation + male sex + family history (affected or unaffected carrier mother) + FISH: Xp22.3 deletion → standard molecular diagnosis + plasma steroid sulfatase assay (very low) + lipoprotein electrophoresis (beta fraction at the start of the lane) → accumulated + histology: normal or thick granular layer + orthokeratotic hyperkeratosis + no agranulosis (unlike ichthyosis vulgaris); autosomal recessive congenital ichthyoses (ARCI) — clinical presentation: lamellar ichthyosis (LI): large, lamellar, brown scales covering the entire body from birth → ectropion (eversion of the eyelids) → eclabium (eversion of the lips) → hypohidrosis (reduced sweating due to obstruction of sweat glands) → risk of heatstroke + acral palmoplantar keratoderma → no erythema or minimal erythema → TGM1 gene most common (30–40% of IL cases) → non-bullous congenital ichthyosiform erythroderma (non-bullous EIC): diffuse erythema + fine, white scales + very red skin + scales thinner than in IL → association with ALOXE3 + ALOX12B + CYP4F22 → congenital ichthyosiform erythroderma with blisters (bullous EIC — epidermolytic ichthyosis — Siemens bullous ichthyosis): mutations in keratin genes 1 (KRT1) and 10 (KRT10) — autosomal dominant → epidermal fragility + blisters + erosions at birth → progression to thick keratosis + brown scales + persistent body odor (bacterial maceration in the scales) → management: topical antibiotic therapy + baths + emollients → collodion baby: presentation of multiple ICCARs → urgent evaluation → rehydration + intensive nursing care (see emergency section); differential diagnosis of ichthyoses: severe atopic eczema (scales associated with inflammation + erythema + severe pruritus + different distribution) + psoriasis (silvery scales + erythema + well-defined plaques + involvement of skin folds + nails) + pityriasis rubra pilaris (orange palms and soles + follicular + patchy distribution) + seborrheic dermatitis (oily scales + scalp + skin folds) + common xerosis (dry skin without true scales + no follicular keratosis) + acquired ichthyosis (adults + systemic evaluation — Hodgkin’s lymphoma +++); structured diagnostic evaluation: history: onset at birth vs. after birth + family history (mode of transmission) + clinical presentation + distribution of scales + morphology (fine vs. thick + brown vs. white vs. grayish) + other findings: pruritus + erythema + blisters + hyperkeratosis + neurological involvement + hypohidrosis → evaluation based on findings: skin biopsy (4 mm punch): histology + electron microscopy if available → functional tests: steroid sulfatase (XLI) assay → lymphocyte enzyme assay (certain ICCAR) → genotyping of the implicated gene based on clinical presentation (multigene panel NGS — Next Generation Sequencing — available at reference centers) + brain imaging + neurological evaluation if Sjögren-Larsson syndrome or KID | Palmer 2006 — Nature Genetics: FLG mutations = primary genetic factor for atopic dermatitis + ichthyosis vulgaris + genotype-phenotype correlation → foundational publication + Oji 2010 — Journal of the American Academy of Dermatology: International consensus classification of ichthyoses → global reference → 1st Ichthyosis Consensus Conference + Rajpopat 2011 — Pediatrics: Harlequin ichthyosis baby → survival to adulthood possible under acitretin + intensive care → 45 patients → reduced early mortality + Comel 1949 + Siemens 1937: Historical descriptions of bullous ichthyoses + Fleckman 2021 — Journal of Investigative Dermatology: Review of molecular mechanisms of ichthyoses + therapeutic implications + Schmuth 2013 — Journal of Investigative Dermatology: Skin barrier pathophysiology in ichthyoses + Oji 2021 — British Journal of Dermatology (EuroSKIN): European recommendations for ichthyosis management + FIRST (Foundation for Ichthyosis and Related Skin Types): North American guidelines for patients and physicians |
| Topical treatment — emollients, keratolytics, and daily care Emollients — salicylic acid — urea — lactic acid — propylene glycol — baths — keratolytic — moisturizing — lipid barrier — moisture |
General principles of topical treatment — the absolute foundation of any management plan: the treatment of ichthyosis is primarily topical and daily → no treatment cures genetic forms → thegoal is to reduce scaling + improve skin hydration + reduce itching + improve quality of life → consistency and frequency of application are just as important as the choice of product; Daily baths — fundamental technique: lukewarm bath (not hot — worsens xerosis) × 10–20 min → softens scales + temporarily hydrates the stratum corneum → add to the water: bath oil (Aveeno Bath Oil + Oilatum) or fine sea salt (osmotic keratolysis) → gentle scrubbing with a soft washcloth (no pumice stone—too harsh) → gentle drying (pat dry—no rubbing) → immediate application of emollients within 3 minutes after the bath (lock-in moisture) → the scalp: keratolytic shampoo (salicylic acid 2–5% + selenium sulfide) + fine-toothed comb to remove scales after softening; emollients — cornerstone of treatment: apply several times a day + systematically after bathing → pure petroleum jelly: occlusive emollient + most economical + excellent for thick scales → shea butter + coconut oil + lanolin → hydration regulators → formulations enriched with physiological lipids: ceramides + cholesterol + free fatty acids → restore the lipid barrier → Epionce + CeraVe + Cetaphil Restoraderm → urea (5–10% in emollients): hygroscopic agent + mildly keratolytic at concentrations >10% → Eucerin Urea 10% + Dermal Therapy → recommended applications: ≥2–3 times/day over the entire body + prefer thick emollients (cream > lotion → greater occlusion) + in the middle of the night: wet wraps: thick emollient + wet bandages + then dry bandages on top → significant improvement in hydration + reduction in scaling; topical keratolytics — for thick scales: salicylic acid: 2–6 times daily as a cream or solution → keratolysis via disruption of interkeratinocyte bonds → effective on areas with thick scales (palms + soles + legs) → avoid the face + mucous membranes + major skin folds (risk of salicylism) → avoid in children <3 years old + premature infants (percutaneous absorption → salicyl toxicity) → lactic acid (alpha-hydroxy acid): 5–12% in lotion or cream → keratolysis + hygroscopic → Lac-Hydrin 12% → effective on large areas + urea 15–40%: powerful keratolytic at these concentrations → Eucerin 30 % Foot Cream → ideal for palms and soles + propylene glycol 40–60 % under occlusion: powerful keratolytic → dissolution of thick scales → apply under plastic wrap at night → followed by application of an emollient → topical retinoids (tazarotene — Tazorac): vitamin A derivatives → regulation of keratinocyte differentiation → indication: moderate ichthyosis vulgaris + XLI → modest efficacy compared to systemic retinoids → frequent skin irritation → contraindicated during pregnancy (teratogenic) → topical corticosteroids: no indication in pure ichthyosis → useful if associated inflammatory component (eczema + Netherton syndrome) + pruritus + treatment of pruritus: sedating H1 antihistamines (hydroxyzine) for flare-ups + intensive moisturization → pruritus in ichthyosis is linked to xerosis + inflammation + stimulation of nerve endings by kallikreins → eye care (ectropion): frequent use of artificial tears + nighttime eye lubricant → ophthalmic ointment + wraparound glasses (protection against dry corneas) → routine ophthalmological evaluation if ectropion | Oji 2021 — British Journal of Dermatology (EuroSKIN recommendations): daily care for ichthyosis → baths + emollients + keratolytics → recommendations based on expert consensus + Not 2012 — British Journal of Dermatology: wet wraps + ichthyosis → significant improvement + occlusive dressing techniques + Loden 2003 — Dermatology: 10% urea in emollient → superior hydration compared to placebo → reduction in xerosis + scaling + Schmuth 2013 — Journal of Investigative Dermatology: ceramides + cholesterol + free fatty acids → restoration of the lipid barrier → greater efficacy than simple emollients → Dreyfus 2014 — Pediatrics: Harlequin baby + early intensive care → improvement in scaling + prevention of complications + Elias 2016 — Journal of Investigative Dermatology: review of keratolytics in ichthyosis → salicylic acid + urea + lactic acid → Chamlin 2005 — Archives of Dermatology: wet wraps + ichthyosis + atopic dermatitis → significant reduction in symptoms + FIRST Foundation: practical guide for patients and families with ichthyosis + options available in Canada + Proksch 2020 — Experimental Dermatology: review of the mechanisms of action of emollients in ichthyosis |
| Systemic retinoids and emerging treatments Acitretin — isotretinoin — retinoids — teratogenicity — monitoring — iPLEDGE program — JAK inhibitors — gene therapy — Harlequin ichthyosis — severe ichthyosis — quality of life |
Systemic retinoids — the only disease-modifying treatment for severe forms: mechanism: synthetic derivatives of vitamin A → regulation of gene transcription involved in keratinocyte differentiation → reduced keratin production + reduced cohesion of corneocytes → reduced scaling + improvement inerythema in ichthyosiform erythrodermas + acitretin (Soriatane): second-generation aromatic retinoid → standard treatment for severe ICCAR (lamellar ichthyosis + ichthyosiform erythroderma) + Harlequin baby → dosage: 0.5–1 mg/kg/day → titration based on efficacy and tolerability → efficacy: 50–70% reduction in scaling in responders → Lacz 1997 — Journal of the American Academy of Dermatology: acitretin + severe ICCAR → significant improvement in 70–80% of patients → variable response depending on genotype → short half-life (acitretin → 50 hours) → advantage over etretinate (very long half-life → 120 days) + but: in the presence of alcohol → acitretin partially converts back to etretinate → TOTAL ABSTINENCE from alcohol while on acitretin + for 2 months afterward → mandatory contraception for 3 years after discontinuation (etretinate possible) → absolute teratogenicity (category X) → strict contraception program in Canada (iPLEDGE-like program) → adverse effects: cheilitis (almost constant) + cutaneous xerosis + xerophthalmia + hair loss + joint pain + tendon calcifications + hypertriglyceridemia + hepatotoxicity → monitoring: lipid and liver function tests before treatment, at 1 month, and every 3 months → isotretinoin (Accutane — Clarus): used in ICCAR if acitretin is unavailable or clinically preferred → dosage: 0.5–1 mg/kg/day → iPLEDGE program in Canada (contraception + monthly pregnancy test + written commitment) → shorter half-life than acitretin → contraception for only 1 month after discontinuation → Harlequin baby — urgent neonatal treatment: acitretin or isotretinoin within the first hours of life → reduces skin stiffness + facilitates breathing + reduces the risk of infection → Rajpopat 2011 — Pediatrics: 45 Harlequin babies → those treated with retinoids early → better survival → intensive nursing essential in parallel; emerging treatments — therapeutic prospects: JAK inhibitors (jakinibs): baricitinib + ruxolitinib + JAK1/2 inhibitors → reduction of inflammation in ichthyoses with a strong inflammatory component (Netherton syndrome) + interleukin-17 inhibitors (secukinumab + ixekizumab) + IL-4/IL-13 inhibitors (dupilumab): promising data in Netherton syndrome + ichthyosis vulgaris with severe atopic component → Avram 2017 — JAAD Case Reports: dupilumab + Netherton syndrome → reduction in erythema + pruritus + Bréimont 2022 — New England Journal of Medicine: dupilumab in severe ichthyosis with atopic component (SIAC) → reduction in scaling + improved quality of life + currently being evaluated in RCTs (ETHOS Program) → gene therapy and antisense oligonucleotides: correction of the FLG gene via CRISPR-Cas9 → experimental → several trials underway for severe ICCAR → not yet available clinically + cholesteryl linolenate (CL) lotion: X-linked ichthyosis → replaces the substrate of steroid sulfatase → Phase 2 trials → promising + N-acetylcysteine: Netherton ichthyosis → reduction in kallikrein activity → pilot studies; quality of life in ichthyosis: major impact → Renner 2009 — British Journal of Dermatology: quality of life scores (DLQI — Dermatology Life Quality Index) severely impaired in all forms of ichthyosis + higher than in psoriasis and atopic dermatitis → profound psychosocial impact → stigmatization + shame + limitations on social, occupational, athletic, and sexual activities → psychological support + support groups (FIRST + Ichthyosis Canada) → workplace and school accommodations → avoid heat and intense exertion (risk of heatstroke in forms with hypohidrosis — ICCAR) + air conditioning essential + loose-fitting, lightweight clothing made of natural fibers (cotton) | Lacz 1997 — Journal of the American Academy of Dermatology: acitretin + ICCAR → significant improvement in 70–80% of patients → gold standard for the efficacy of systemic retinoids + Rajpopat 2011 — Pediatrics: 45 Harlequin babies → early acitretin + intensive care → improved survival → standard neonatal treatment + Renner 2009 — British Journal of Dermatology: DLQI in ichthyosis → more severe impact than psoriasis + eczema + Bréimont 2022 — NEJM: dupilumab in ichthyosis with a Th2 component → reduction in symptoms → open-label data + Avram 2017 — JAAD Case Reports: dupilumab + Netherton syndrome → reduction in erythema + pruritus + Palmer 2006 — Nature Genetics: FLG mutations + atopic dermatitis → founder effect + Oji 2021 — British Journal of Dermatology (EuroSKIN): comprehensive European guidelines → topical + systemic treatment + multidisciplinary care + Dreyfus 2014 — Pediatrics: Harlequin baby + intensive care → role of retinoids + respiratory physical therapy + parenteral nutrition → FIRST (Foundation for Ichthyosis and Related Skin Types): North American reference guide for patients + Health Canada: iPLEDGE program → contraceptive monitoring during retinoid therapy |
| Collodion baby care, pediatric situations, and genetic counseling Collodion baby — NICU — nursing — premature — infectious risk — hyperthermia — ectropion — genetic counseling — prenatal screening — NGS panel |
Collodion baby — neonatal emergency: initial management in the NICU (neonatal intensive care unit): humidified incubator at 60–80% relative humidity → reduced water evaporation + risk of hypernatremic dehydration → appropriate incubator temperature (risk of hypothermia or hyperthermia) → peripheral or umbilical venous access → infusion of NaCl + glucose solution → strict monitoring of fluid balance → non-irritating emollients applied every 3–4 hours (petroleum jelly + Aquaphor) → eye care: instillation of artificial tears + nail protection → lip care (cleft lip): lubricant + protection of the corners of the mouth + infection prevention: collodion membrane = entry point for germs → regular skin culture samples → antibiotic therapy if superinfection (S. aureus ++) + preventive antibiotic therapy discussed → neurological and nutritional monitoring (dysphagia if cleft lip) → re-evaluation of the membrane: it cracks and then gradually peels off over 2–4 weeks → reveals the underlying type of ichthyosis → transfer to a specialized dermatology unit + self-healing collodion baby: 10–20 1–3-year-old infants-collodion → near-normal skin after membrane desquamation → genetically linked to ALOX12B + ALOXE3 + or TGM1 with hypomorphic mutation → remote dermatological follow-up + long-term pediatric management of ichthyosis: diet: no specific dietary restrictions + monitor growth (some ICCAR → growth delay + malabsorption of cutaneous lipids) + pain and mobility: physical therapy + occupational therapy → maintenance of joint mobility (risk of contractures in severe forms) + schooling: accommodations (accessible shower + time allocated for care during the day + permission to drink + appropriate clothing + no sunbathing / heat exposure) + heat management / hypohidrosis: risk of heatstroke in ICCAR with hypohidrosis (obstruction of sweat ducts) → informing parents and the school + cooling clothing (Coolshirt + clothing with cooling crystals) + water sprayers + air conditioning → enrollment in a regular dermatological monitoring program; genetic counseling: ichthyosis vulgaris AD: autosomal dominant → 50% risk of transmission → incomplete penetrance → highly variable phenotype depending on mutations + XLI: X-linked recessive → complex genetic counseling (carrier mothers) → screening of carrier daughters → risk of delayed delivery (cholesteryl sulfate) + ICCAR: autosomal recessive → 25% risk for each pregnancy of two carrier parents → prenatal screening: chorionic villus sampling (10–12 weeks gestation) + amniocentesis (15–17 weeks gestation) → molecular analysis if familial mutations identified → genetic counseling by a specialist + PGD (preimplantation genetic diagnosis): possible if mutations identified → prior genetic consultation → NGS (Next Generation Sequencing) multigene panel at reference centers: ichthyosis panels including FLG + STS + TGM1 + ABCA12 + ALOX12B + ALOXE3 + CYP4F22 + NIPAL4 + PNPLA1 + KRT1 + KRT10 + SPINK5 + GJB2 + 30–50 other genes → diagnostic yield 60–70% in typical forms of ICCAR | Dreyfus 2014 — Pediatrics: Harlequin baby in NICU → early retinoids + intensive care → improved survival → management recommendations. Not 2012 — British Journal of Dermatology: Collodion baby → NICU care protocol → humidity + emollients + ectropion monitoring. Oji 2010 — JAAD: International classification → self-resolving collodion baby identified as a distinct entity. Fleckman 2021 — JID: NGS panel in ichthyoses → diagnostic yield + therapeutic implications. Schmuth 2013 — JID: Pathophysiology + therapeutic implications → prognostic markers. Oji 2021 — BJD (EuroSKIN): Multidisciplinary management → pediatric care + retinoids + school counseling + quality of life. Renner 2009 — BJD: DLQI + ichthyosis → significantly impaired + psychosocial support needed. FIRST Foundation + Ichthyosis Canada: Patient support groups + families in Canada → French-language resources available. Health Canada + SOGC: Genetic prenatal screening → genetic counseling in regional medical genetics centers (CHU Sainte-Justine + CHU de Québec + CHU McGill). |
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The treatment of ichthyosis is primarily daily and lifelong—applying emollients multiple times a day after bathing is the most effective measure for all forms: No treatment can cure genetic ichthyosis, but thick emollients, keratolytics (10–20% urea + lactic acid), and systemic retinoids for severe forms can significantly improve quality of life. Patients with ichthyosis and hypohidrosis (ICCAR) are at risk of heatstroke during physical exertion or in hot environments—this information should be shared with parents, teachers, and employers.
Situations requiring urgent consultation or transfer to the NICU
Newborn wrapped in a taut parchment-like membrane (collodion membrane) with ectropion, eclabium, restricted breathing and/or limb movements → Collodion baby → Immediate transfer to NICU → Humidified incubator + emollients every 3–4 hours + monitoring for dehydration and thermoregulation + eye care + infection surveillance + acitretin if Harlequin ichthyosis is suspected (massive hexagonal keratotic scales).
Child with congenital ichthyosis with anhidrosis (CICH) presenting with hyperthermia >39°C + absence of sweat during exertion or heat exposure → Heatstroke due to hypohidrosis → Pediatric emergencies → Immediate cooling (water + fan + tepid bath) + IV infusion if severe hyperthermia → Inform parents about prevention + air conditioning + cooling clothing.
Patient on acitretin or isotretinoin presenting with severe abdominal pain + nausea + vomiting + hypertriglyceridemia >10 mmol/L → Iatrogenic acute pancreatitis under retinoids → immediate discontinuation of treatment + medical emergency → IV hydration + fasting + hospitalization monitoring → do not restart retinoid without dermatologist's advice.
Woman under acitretin or isotretinoin (severe ichthyosis treated) with missed period or positive pregnancy test → Retinoid pregnancy → Teratological emergency → Immediate obstetrical and teratological consultation (Motherisk Center or Quebec equivalent) → risk assessment + informed consent + acitretin: mandatory contraception for 3 years after stopping.
Consult at Clinique Omicron
The doctors at Clinique Omicron evaluate chronic scaly skin conditions suspected of being ichthyosis, prescribe emollients and keratolytics suited to the clinical type, refer patients to dermatologists and geneticists for molecular analysis and genetic counseling, and manage complications (superinfection, ectropion, hypohidrosis). Consultations are available at several service points in Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
The content of this page is provided for informational purposes only and does not substitute for the advice of a dermatologist or a medical geneticist. Severe ichthyoses require multidisciplinary management at a reference center.
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