by the presence of fishlike scales (ICHTHYS)
? Scaling is generally worse in winter.
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? Ichthyotic disorders are usually inherited but may be acquired
? Scale: flat plate or flake of
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stratum corneum
ICHTHYOSIS VULGARIS
? Etiology
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?Inheritance: AD.?Molecular defect: Reduced or absent filaggrin3.
? Epidemiology
?Prevalence: Common disorder (incidence of 4/1000).
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?Age of onset:3?12 months.?Gender predilection: Males = Females.
? Character of scales: On most parts of body: Fine, white scales.
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? On extensors of lower extremities (most severely affected parts):Large scales, attached (pasted) at center and turned up at the edge,
making skin rough. Superficial fissuring may develop on shins in
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winter.
? Distribution: Extensors of limbs, lower back. Flexures spared
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? Associated features: Keratosis pilaris, hyperlinear palms and soles,atopic diathesis
? Investigations- None needed
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? Skin biopsy:
? Hyperkeratosis with Hypogranulosis or absent granular layer
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? Diagnosis : CLINICAL?Points for diagnosis : Diagnosis of IV is based on the presence of:
Scales, which are generally fine (white) but are larger and pasted on
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the shins. Characteristic distribution on extensors with conspicuoussparing of major flexures. Associations: Hyperlinear palms, keratosis
pilaris and atopic diathesis.
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? Treatment: USUALLY REQUIRED IN WINTERS? Hydration (by immersing in water) and immediate lubrication
(petrolatum; urea+glycerine+water) of skin.
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? Use keratolytic agents (hydroxy acids, propylene glycol, and salicylicacid) when severe.
X-LINKED ICHTHYOSIS
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? Etiology
? Inheritance: XLRI .
? Molecular defect: Deficiency of enzyme steroid sulfatase.
? Epidemiology Prevalence : 1: 5000 males. Age of onset: At birth.
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Gender predilection:Affects only males
? Character of scales: Large, adherent and brown (sometimes almost
black
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? Sites of predilection:
? Generalized involvement with no (only minimal) sparing of the body
flexures.
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?Scales most pronounced on the posterior aspect of neck, extensors of
arms and legs encroaching cubital and popliteal fossa.
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?Palms and soles spared? Associated features
?Comma-shaped corneal opacities (do not interfere with vision).
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?Cryptorchidism
? Investigations
? Skin biopsy (if done) shows: Hyperkeratosis
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? Hypergranulosis (cf., IV, where granular layer is absent or thin).? Elevated serum cholesterol sulfate.
? Lowered steroid sulfatase in fibroblasts cultured from a skin biopsy
(done for research purposes).
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? Diagnosis
? Points for diagnosis:
? Patient being male
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?Presence of large, dark, adherent scales?Involvement of extensors with encroachment of flexures.
? Treatment Measures as for IV
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Lamellar Ichthyosis (LI)? Epidemiology: Rare.
? Etiology: AR.
? Abnormality of gene encoding for transglutaminase.
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? Onset: At birth, as collodion baby. ensheathed in a membrane; when
the membrane sheds, typical scales become apparent.
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? Character of scale: Large thick, brown, pasted scales.? Distribution: Generalized, including flexures
? Treatment: Mild cases: Manage with hydration, lubrication and
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keratolytics.
? Severe cases: Acitretin
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? Associated features
? Ectropion and eclabium
? Rippled hyperkeratosis around
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joints.
? Palmar and plantar keratoderma
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frequent.? Crumpled ears
? Diagnosis
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?History of collodion membrane at birth?Characteristic thick, large, brown, pasted scales,especially on the
shins.
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?Continuous rippling around joints.?Minimal erythema (except on face).
? Differential diagnosis : NBIE
? Treatment
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? Mild cases: Managed as patients with IV .? Severe cases: Acitretin, under careful supervision.
Nonbul ous Ichthyosiform Erythroderma (NBIE)
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? Etiology: AR.? Onset: At birth, as collodion membrane.
? Character of scales: On shedding of collodion membrane, there is
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fine diffuse scaling on background of erythema.
? Distribution: Generalized.
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? Diagnosis
?Presence of collodion membrane at birth.
?Presence of small branny scales on a background of diffuse erythema.
?Generalized involvement.
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? Treatment: As for LI.
Epidermolytic Hyperkeratosis (EHK)
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? Etiology: AD.
? Onset: Self-limiting blistering stage.
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? Character of scales: Brown hyperkeratotic (warty) waxy scalesforming broad linear lesions with skip areas.
? Distribution: Generalized with accentuation in flexures.
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? Associations: Palmoplantar keratoderma.
? Treatment: Emollients. Mild disease: Topical retinoic acid (care in
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flexures!).
? Extensive disease: Systemic retinoids.
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Collodion Baby
? A morphological diagnosis.
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? Most frequently associated with an underlying ichthyotic disorder:?Nonbullous ichthyosiform erythroderma
?Lamellar ichthyosis.
? Clinical Features:
? Neonate is born with a smooth and shiny skin(lacquered
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appearance), as if covered with cellophane or collodion . Tightness of
the skin causes ectropion and eclabium.
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? Outer cover (which is present all over the body) is eventually shed toreveal the underlying ichthyosis.
? Complications:
? Temperature dysregulation.
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?Feeding difficulties due to eclabium.?Water and electrolyte imbalance
? Variants :
? Harlequin fetus:
?Where the skin is covered with thick fissured skin resembling an
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armor.
?Often fatal.
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? TreatmentvHigh-humidity incubator nursing necessary to maintain body
temperature and to restrict water loss.
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vRegular application of emollients to make skin supple.
vShort course of acitretin (oral retinoid) hastens shedding.
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Acquired Ichthyosis? If ichthyosis appears in adult life,
suspect an underlying cause
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? Clinical features resemble IV
? Symptomatic treatment with
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topical emollients afterhydration.
? Treatment of underlying
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problem often reverses the
ichthyosis.
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