Download MBBS Dermatology PPT 10 Ichthyosis And Ichthyosiform Disorders Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Dermatology PPT 10 Ichthyosis And Ichthyosiform Disorders Lecture Notes

ICHTHYOSIS AND

ICHTHYOSIFORM DISORDERS

? Ichthyoses are a heterogeneous group of dermatoses characterized

by the presence of fishlike scales (ICHTHYS)

? Scaling is generally worse in winter.

? Ichthyotic disorders are usually inherited but may be acquired


? Scale: flat plate or flake of

stratum corneum
ICHTHYOSIS VULGARIS

? Etiology
?Inheritance: AD.
?Molecular defect: Reduced or absent filaggrin3.

? Epidemiology
?Prevalence: Common disorder (incidence of 4/1000).
?Age of onset:3?12 months.
?Gender predilection: Males = Females.

? Character of scales: On most parts of body: Fine, white scales.

? 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

winter.

? Distribution: Extensors of limbs, lower back. Flexures spared

? Associated features: Keratosis pilaris, hyperlinear palms and soles,

atopic diathesis

? Investigations- None needed

? Skin biopsy:

? Hyperkeratosis with Hypogranulosis or absent granular layer

? 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

the shins. Characteristic distribution on extensors with conspicuous

sparing of major flexures. Associations: Hyperlinear palms, keratosis

pilaris and atopic diathesis.
? Treatment: USUALLY REQUIRED IN WINTERS
? Hydration (by immersing in water) and immediate lubrication

(petrolatum; urea+glycerine+water) of skin.

? Use keratolytic agents (hydroxy acids, propylene glycol, and salicylic

acid) when severe.

X-LINKED ICHTHYOSIS

? Etiology
? Inheritance: XLRI .
? Molecular defect: Deficiency of enzyme steroid sulfatase.
? Epidemiology Prevalence : 1: 5000 males. Age of onset: At birth.

Gender predilection:Affects only males
? Character of scales: Large, adherent and brown (sometimes almost

black

? Sites of predilection:
? Generalized involvement with no (only minimal) sparing of the body

flexures.

?Scales most pronounced on the posterior aspect of neck, extensors of

arms and legs encroaching cubital and popliteal fossa.

?Palms and soles spared

? Associated features

?Comma-shaped corneal opacities (do not interfere with vision).

?Cryptorchidism

? Investigations
? Skin biopsy (if done) shows: Hyperkeratosis
? 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).


? Diagnosis
? Points for diagnosis:
? Patient being male
?Presence of large, dark, adherent scales
?Involvement of extensors with encroachment of flexures.


? Treatment Measures as for IV
Lamellar Ichthyosis (LI)

? Epidemiology: Rare.
? Etiology: AR.
? Abnormality of gene encoding for transglutaminase.

? Onset: At birth, as collodion baby. ensheathed in a membrane; when

the membrane sheds, typical scales become apparent.

? Character of scale: Large thick, brown, pasted scales.

? Distribution: Generalized, including flexures

? Treatment: Mild cases: Manage with hydration, lubrication and

keratolytics.

? Severe cases: Acitretin



? Associated features
? Ectropion and eclabium
? Rippled hyperkeratosis around

joints.

? Palmar and plantar keratoderma

frequent.

? Crumpled ears

? Diagnosis
?History of collodion membrane at birth
?Characteristic thick, large, brown, pasted scales,especially on the

shins.

?Continuous rippling around joints.
?Minimal erythema (except on face).
? Differential diagnosis : NBIE

? Treatment
? Mild cases: Managed as patients with IV .
? Severe cases: Acitretin, under careful supervision.

Nonbul ous Ichthyosiform Erythroderma (NBIE)

? Etiology: AR.

? Onset: At birth, as collodion membrane.

? Character of scales: On shedding of collodion membrane, there is

fine diffuse scaling on background of erythema.

? Distribution: Generalized.


? Diagnosis
?Presence of collodion membrane at birth.
?Presence of small branny scales on a background of diffuse erythema.
?Generalized involvement.

? Treatment: As for LI.


Epidermolytic Hyperkeratosis (EHK)

? Etiology: AD.

? Onset: Self-limiting blistering stage.

? Character of scales: Brown hyperkeratotic (warty) waxy scales

forming broad linear lesions with skip areas.

? Distribution: Generalized with accentuation in flexures.


? Associations: Palmoplantar keratoderma.

? Treatment: Emollients. Mild disease: Topical retinoic acid (care in

flexures!).

? Extensive disease: Systemic retinoids.


Collodion Baby

? A morphological diagnosis.

? 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

appearance), as if covered with cellophane or collodion . Tightness of

the skin causes ectropion and eclabium.

? Outer cover (which is present all over the body) is eventually shed to

reveal the underlying ichthyosis.
? Complications:
? Temperature dysregulation.
?Feeding difficulties due to eclabium.
?Water and electrolyte imbalance
? Variants :
? Harlequin fetus:
?Where the skin is covered with thick fissured skin resembling an

armor.

?Often fatal.

? Treatment

vHigh-humidity incubator nursing necessary to maintain body

temperature and to restrict water loss.

vRegular application of emollients to make skin supple.
vShort course of acitretin (oral retinoid) hastens shedding.


Acquired Ichthyosis

? If ichthyosis appears in adult life,

suspect an underlying cause

? Clinical features resemble IV

? Symptomatic treatment with

topical emollients after

hydration.

? Treatment of underlying

problem often reverses the

ichthyosis.