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Dermatology Board Prep > DERM (09) Genodermatoses > Ichthyoses, Erythrokeratodermas, and Related Disorders > Flashcards

Ichthyoses, Erythrokeratodermas, and Related Disorders Flashcards

1
Q

When do inherited ichthyoses usually show up?

A

Birth or in infancy/early childhood

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2
Q

What is the unifying finding in inherited ichthyoses?

A

Abnormal epidermal differentiation or metabolism –> hyperkeratosis and/or epidermal hyperplasia

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3
Q

What is the underlying pathology of the inherited ichthyoses?

A

Dysfunction of cornified cell envelope disrupts skin barrier function which leads to increased transepidermal water loss

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4
Q

In what conditions can a Collodion membrane be seen in?

A

Lamellar ichthyosis and non- bullous congenital erythroderma is most common; also Sjögren-Larsson syndrome, Gaucher disease type 2, Hay-Well syndrome, trichothyodystrophy, Netherton syndrome, ectodermal dysplasia, and neutral lipid storage disease

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5
Q

How long does it take for the collodion membrane to resolve?

A

Several weeks

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6
Q

What are some important findings on histology in the ichthyoses?

A

Ichthyosis Vulgaris = diminished or absent granular layer

  • Epidermolytic ichthyosis shows epidermolytic hyperkeratosis
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7
Q

What are some treatments that are important in the inherited inchtyosis?

A

General: Emollients and keratolytics; topical and systemic retinoids can help reduce hyperkeratosis

Neonatal tx: humidified incubators, emollients and close observation for infection, dehydration, and electrolyte abnormalities (hypernatremia from dehydration)

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8
Q

What are the 3 main types of palmoplantar keratodermas?

A

focal (localized areas of hyperkeratosis, usually over pressure points), diffuse (hyperkeratosis involves entire palmoplantar surface), and punctate (1- to 2-mm keratotic papules)

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9
Q

What is the treatment of palmoplantar keratodermas?

A

Topical keratolytics like salicylic acid, urea, etc, topical retinoids, and topical corticosteroids if inflamed.

  • If severe can consider oral retinoids, CO2 laser and surgical paring or excision
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10
Q

What gene is mutated in Ichthyosis Vulgaris?

A

Filaggrin (FLG)

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11
Q

What is the inheritance in Ichthyosis Vulgaris?

A

Autosomal semidominant

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12
Q

What is the onset of Ichthyosis Vulgaris?

A

Infancy/childhood

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13
Q

What are the main skin findings in Ichthyosis Vulgaris?

A
  • Fine, adherent scales on extremities and trunk with sparing of flexures
  • Larger scale on lower legs
  • Hyperlinear palms/soles, and furrowed heels
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14
Q

Associated clinical findings with Ichthyosis Vulgaris?

A

Keratosis Pilaris

  • Atopic diathesis
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15
Q

Histology of Ichthyosis Vulgaris?

A

Diminished/absent stratum granulosum w/overlying orthohyperkeratosis

  • Absent/reduced filaggrin immunostaining
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16
Q

What is the gene involved in steroid sulfatase deficiency (x-linked recessive ichthyosis)?

A

STS

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17
Q

The inheritance pattern in steroid sulfatase deficiency (x-linked recessive ichthyosis)?

A

x-linked recessive (continuous gene deletion may lead to Kallmann syndrome)

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18
Q

What is the onset of steroid sulfatase deficiency (x-linked recessive ichthyosis)?

A

Infancy

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19
Q

What are the primary cutaneous findings in steroid sulfatase deficiency (x-linked recessive ichthyosis)?

A

Fine to large, dark/brown, adherent scales on extremities, trunk, neck, and lateral face spares flexures, palms, soles, and face

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20
Q

What are some associated clinical features of steroid sulfatase deficiency (x-linked recessive ichthyosis)?

A

Corneal (comma-shaped) opacities; cryptorchidism; increased risk of testicular cancer, and hypogonadism

  • Female carriers: corneal opacities; prolonged labor with affected child (placental sulfatase deficiency)
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21
Q

What is the histologic features of steroid sulfatase deficiency (x-linked recessive ichthyosis)?

A

Retained corneodesmosomes within the stratum corneum

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22
Q

What other lab abnormalities are seen in steroid sulfatase deficiency (x-linked recessive ichthyosis)?

A

Lipoprotein electrophoresis (increased mobility of β-fraction); plasma cholesterol sulfate increased; decreased steroid sulfatase activity in leukocytes; FISH, array CGH, genetic testing

  • Maternal carriers may have abnormal triple/ quad screen during affected pregnancy with decreased serum estriol
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23
Q

What gene is mutated in lamellar ichthyosis?

A

Mostly TGM1 is most common

Also: ABCA12, CYP4F22, CERS3

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24
Q

Inheritance pattern of lamellar ichthyosis?

A

AR

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25
Q

Onset of lamellar ichthyosis?

A

Birth

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26
Q

What are the primary skin findings in lamellar ichthyosis?

A
  • Often have collodion membrane at birth w/ ectropion and eclabium
  • After collodion resolves –> presence of large, thick, plate-like brown scales
  • Generalized distribution w/significant flexural involvement; absent or mild erythroderma; variable palm/ sole involvement (PPK)
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27
Q

Other clinical features in lamellar ichthyosis?

A

Heat intolerance (hypernatremic dehydration); often have scarring alopecia; dystrophic nails

  • Hyperhidrosis
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28
Q

What are the histologic findings in lamellar ichthyosis?

A

They vary depending on the underlying gene etiology:

TGM1: Thin cornified envelope and disorganized lamellar bilayers

ABCA12: Absence of lamellar body content

NIPAL4: Defective lamellar bodies and perinuclear membranes within stratum granulosum

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29
Q

What is the most common cause of collodion baby?

A

Congenital ichthyosiform erythroderma

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30
Q

What are the genes involved in Congenital ichthyosiform erythroderma?

A

Big ones to remember: ALOXE3, ALOX12B

Others: TGM1, NIPAL4 (ICHTHYIN), PNPLA1

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31
Q

What is the inheritance pattern for Congenital ichthyosiform erythroderma?

A

AR

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32
Q

What is the time of onset for Congenital ichthyosiform erythroderma?

A

Birth

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33
Q

What are the primary skin findings in Congenital ichthyosiform erythroderma?

A

After collodion resolves, there is fine, white scale, in generalized distribution with the flexures involved

The erythroderma is variable with palm/sole involvement

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34
Q

Other clinical findings in Congenital ichthyosiform erythroderma?

A

Heat intolerance/hypohidrosis; variable scarring alopecia and ectropion

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35
Q

What are the genetic and clinical features of congenital self-healing collodion baby?

A

AR, TGM1, ALOXE3, ALOX12B, the onset is birth

  • Collodion membrane at birth; after resolution, the skin appears normal without the features of ichthyosis
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36
Q

What is the gene and the inheritance pattern of harlequin ichthyosis?

A

ABCA12

AR

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37
Q

What is the onset of harlequin ichthyosis?

A

Birth

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38
Q

What are the primary skin findings in harlequin ichthyosis?

A

Very thick, yellow-brown plates of scale with large, deep and bright red fissures that tightly encase the neonate

  • Also has extreme ectropion, eclabium, and ear deformities
  • Survivors develop severe CIE-like phenotype
  • Early initiation of systemic retinoids and specialized neonatal intensive care reduces mortality
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39
Q

What is the treatment for Harlequin ichthyosis?

A

Early initiation of systemic retinoids and specialized neonatal intensive care reduces mortality

40
Q

What other lab and clinical abnormalities are important to watch for in Harlequin ichthyosis?

A

Premature delivery

  • Neonatal hypothermia
  • Hypernatremic dehydration
  • Most common cuases of death are sepsis and respiratory insufficiency
41
Q

Histologic findings in Harlequin ichthyosis?

A

Vesicular lamellar body ghosts, a paucity of secreted lamellar structures in stratum corneum

42
Q

What is the inheritance pattern and genes involved in epidermolytic ichthyosis (bullous CIE)?

A

Genes: KRT1, KRT10

AD

May have somatic mosaicism, extensive epidermal nevi (ichthyosis hystrix); if it is gonadal mosaicism, then may have offspring with full-blown disease

43
Q

What are the primary cutaneous findings in epidermolytic ichthyosis?

A
  • At birth: erythroderma, blistering, and erosions
  • Later: hyperkeratosis with cobblestone pattern (most prominent over joints), ridging of the flexures; generalized or localized; the variable degree of erythroderma, palmoplantar involvement, and blistering/ bullae
  • Retinoids can exacerbate skin fragility
44
Q

Other non-cutaneous findings in epidermolytic ichthyosis?

A

Frequent skin infections

Malodor

Gait and posture abnormalities

45
Q

What is the histology of in epidermolytic ichthyosis?

A

Hyperkeratosis, keratinocyte vacuolization, and a prominent granular layer with clumped keratin in suprabasal cells

-Lamellar body accumulation

46
Q

What is the inheritance pattern and genes involved for superficial epidermolytic ichthyosis (ichthyosis bullosa of Siemens)?

A

KRT2

AD

47
Q

Time of onset for superficial epidermolytic ichthyosis (ichthyosis bullosa of Siemens)?

A

Birth

48
Q

Primary cutaneous findings in superficial epidermolytic ichthyosis (ichthyosis bullosa of Siemens)?

A

Birth: Erythroderma and superficial blistering

Later: hyperkeratosis with accentuation over joints, flexures, and dorsal hands/ feet; “molting” of the skin; palms and soles spared

49
Q

Histologic findings of superficial epidermolytic ichthyosis (ichthyosis bullosa of Siemens)?

A

Cytolysis of granular cells

50
Q

What is the gene involved and the inheritance pattern for ichthyosis hystrix Curth-Macklin?

A

KRT1

AD

51
Q

What is the time of onset for ichthyosis hystrix Curth-Macklin?

A

Birth

52
Q

What are the primary cutaneous findings in ichthyosis hystrix Curth-Macklin?

A
  • Mild to severe mutilating palmoplantar keratoderma
  • Hyperkeratosis w/ verrucous, cobblestone, or hystrix-like pattern on extremities and trunk. These scales can often have a spiny appearance
53
Q

Genetic inheritance pattern, gene involved, and prevalence of ichthyosis en confetti?

A

KRT10

AD

<20 cases described

54
Q

Cutaneous findings in ichthyosis en confetti?

A

Birth: Erythroderma and scaling

Later: Confetti-like areas of scaling (result from revertant mosaicism); palmoplantar keratoderma

55
Q

Histologic findings in ichthyosis en confetti?

A

Affected skin: loss of epidermal differentiation above the basal
layer with nucleolar vacuolization, loss of granular layer, and acanthosis

Revertant skin: normal

56
Q

What are the involved genes in Netherton syndrome?

A

SPINK5 (encodes LEKT1, a serine protease inhibitor)

57
Q

What is the mode of inheritance in Netherton Syndrome?

A

AR

58
Q

What are the primary cutaneous findings in Netherton syndrome?

A

Congenital erythroderma w/ scaling

  • There are 2 principle phenotypes of the dz:
  1. Ichthyosis linearis circumflexa (annular or serpiginous plaques w/ double-edged scale
  2. CIE-like: pruritus and eczematous plaques
59
Q

What treatment should not be used in Netherton syndrome?

A

Tacrolimus ointment

  • There is increased absorption due to skin barrier defect and there can be toxic effects from this
  • Also should avoid keratolytics as these can be irritating
60
Q

What are the other non-skin findings in Netherton syndrome?

A

Trichorrehexis invaginata

trichorrhexis nods can also be seen and pili tori (short/sparse hair and borws)

Increased IgE

Neonatal temperature instability, electrolyte abnormalities (hyponatremia), failure to thrive and infections

  • Food and other allergies/analphylaxis are important to be aware of
61
Q

Histology seen in Netherton syndrome?

A

Psoriasiform morphology

  • Hair shaft light microscopy cna show trichorrhexis invaginata (bamboo hair, looks like ball in socket up close)
62
Q

What is the inheritance pattern and genes seen in Sjögren-Larsson syndrome?

A

ALDH3A2/FALDH
- AR

63
Q

Primary skin findings in Sjögren-Larsson syndrome?

A

Birth: Erythema and hyperkeratosis

Later: Fine to plate-like/dark scaling or nonscaling hyperkeratosis

  • Tends to favors abdomen, neck, flexures; lichenification
  • Can see palmoplantar keratoderma
  • The pruritus can be severe
64
Q

Other non-skin associated findings in Sjögren-Larsson syndrome?

A

Progressive spastic di- and tetraplegia; developmental delay; intellectual disability; seizures; perifoveal glistening white dots; white matter disease of the brain; photophobia

65
Q

What is the genetic inheritance and gene involved in Neutral lipid storage disease with ichthyosis/Chanarin-Dorfman syndrome?

A

ABHD5 (CGI-58)

AR

66
Q

What are the primary cutaneous findings in Neutral lipid storage disease with ichthyosis/Chanarin-Dorfman syndrome?

A

Generalized, fine, white scales with variable erythema

67
Q

Other non-cutaneous findings in Neutral lipid storage disease with ichthyosis/Chanarin-Dorfman syndrome?

A

Developmental delay; hepatomegaly with liver fibrosis, elevated liver enzymes, and creatine kinase; myopathy; hearing impairment; cataracts

68
Q

What histologic findings are seen in Neutral lipid storage disease with ichthyosis/ Chanarin-Dorfman syndrome?

A

Globular electron- lucent inclusions in the epidermis

69
Q

What other lab abnormalities can be seen in Neutral lipid storage disease with ichthyosis/ Chanarin-Dorfman syndrome?

A

Peripheral blood smear to detect lipid vacuoles in granulocytes, eosinophils, and monocytes; oil stains of frozen tissue

70
Q

What are the genes involved and the mode of inheritance for Refsum disease?

A

PHYH/PEX7

AR

71
Q

What is the time of onset for Refsum disease?

A

Childhood to adulthood

72
Q

What are the primary cutaneous findings in Refsum disease?

A

Fine, white scales on extremities and trunk, resembling ichthyosis vulgaris (50%)

73
Q

What are the non-cutaneous other findings in Refsum disease?

A

Peripheral motor and sensory neuropathy

  • Cranial nerve dysfunction (deafness, anosmia)
  • Cerebellar ataxia
  • Atypical retinitis pigmentosa (“salt and pepper pigment”)
  • Cardiac: cardiomyopathy, arrhythmias w/ heart block
  • Muscle wasting
74
Q

Histologic findings in Refsum dz?

A

Orthokeratotic hyperkeratosis and lipid-containing vacuoles in basal keratinocytes

75
Q

What are the other lab abnormalities seen in Refsum disease?

A

Increased plasma phytanic acid; phytanoyl-CoA hydroxylase activity assay in cultured fibroblasts

76
Q

What is the important dietary modification needed in Refsum disease?

A

Diet is essential: decrease green vegetables, dairy products, and ruminant fats

77
Q

What is the mode of inheritance and gene involved in Keratitis-ichthyosis-deafness syndrome?

A

GJB2 (encodes connexin 26)

AD (usually sporadic)

78
Q

What are the primary cutaneous findings in Keratitis-ichthyosis-deafness syndrome?

A

Transient neonatal erythroderma

  • Erythematous, hyperkeratotic plaques w/ well-demarcated, borders on face and extremities
  • Follicular keratoses
  • Thickening of the skin with an appearance of “coarse-grained leather;” stippled palmoplantar keratoderma
79
Q

What are the main non-cutaneous findings in Keratitis-ichthyosis- deafness syndrome?

A

Congenital sensorineural hearing impairment

  • Progressive keratitis with corneal neovascularization that may lead to blindness, conjunctivitis
  • Recurrent mucocutaneous infections, especially with Candida albicans
  • Increased susceptibility to oral and cutaneous squamous cell carcinoma
  • Other: nail, hair, and dental anomalies; cheilitis
80
Q

What is the mode of inheritance and the involved gene in Eryhthrokeratodermia variabilis?

A

GJB3/GJB4 (encode connexion 31, GJA1 and 30.3)

AD

81
Q

Primary skin findings in Eryhthrokeratodermia variabilis?

A

Transient, variable, erythematous patches

  • More stable, geographic, hyperkeratotic plaques over knees, elbows, Achilles tendons, extremities, buttocks, and lateral trunk
  • Face and scalp often spared
  • Less common generalized hyperkeratosis
  • Palmoplantar keratoderma in ~50% of patients
82
Q

What are the genes and mode of inheritance for progressive symmetric erythroderkatoderma?

A

LOR, GJB4, other

AD or AR

83
Q

Primary cutaneous findings in progressive symmetric erythroderkatoderma?

A

Fixed, slowly progressive, erythematous, hyperkeratotic plaques with sharp, figurate borders; on cheeks, over knees, elbows, extremities, and rarely trunk

  • Palmoplantar keratoderma common
84
Q

What is the mode of inheritance and gene involved in Acral peeling skin syndrome?

A

TGM5

AR

85
Q

Primary cutaneous findings in Acral peeling skin syndrome?

A

Recurrent spontaneous painless superficial peeling on dorsal hands and feet, followed by the development of mild erythema;
resolves without scarring

  • Exacerbated by heat and humidity
86
Q

Histologic findings in Acral peeling skin syndrome?

A

Separation occurs between the junction of the stratum granulosum and the stratum corneum

87
Q

What is the mode of inheritance and gene involved in congenital hemidysplasia with ichthyosiform erythroderma and limb defects (CHILD sydnrome)

A

NSDHL ( 3beta-hydroxysteroid-dehydrogenase)

XLD (occurs nearly exclusively in women)

88
Q

What are the primary cutaneous sx’s of congenital hemidysplasia with ichthyosiform erythroderma and limb defects (CHILD sydnrome)

A

Birth: Unilateral (right > left-sided) erythema and waxy, yellowish adherent scale on 1/2 of the body (trunk/ extremities)

Later: Verrucous hyperkeratosis of variable extent, with an affinity for skin folds

89
Q

What are the non-clinical associated clinical features of Congenital hemidysplasia with ichthyosisiform erythroderma
and limb defects (CHILD) syndrome

A

Ipsilateral skeletal hemidysplasia (hypoplastic limbs)

  • Ipsilateral organ hypoplasia; ipsilateral alopecia
  • May also see stippled epiphyses/ chondrodysplasia punctata (similar to Conradi-Hunermann- Happle)
90
Q

What is the gene affected and the inheritance of Conradi-Hünermann- Happle syndrome (X-linked dominant chrondrodysplasia punctata)?

A

EBP (emopamil-binding protein)

XLD (exclusively affects women)

91
Q

Primary cutaneous findings in Conradi-Hünermann- Happle syndrome (X-linked dominant chrondrodysplasia punctata)?

A

Birth: Ichthyosiform erythroderma (generalized, vs unilateral in CHILD syndrome) with feathery, adherent scale along Blaschko’s lines

Later: The erythema resolves in first few months of life (unlike CHILD syndrome) and is replaced by follicular atrophoderma along Blaschko’s lines, most prominently on the forearms and dorsal hands

92
Q

What are the main non-cutaneous clinical features of Conradi-Hünermann- Happle syndrome (X-linked dominant chrondrodysplasia punctata)?

A

Unilateral cataracts; stippled epiphyses/chondrodysplasia punctata seen only during infancy; asymmetric skeletal abnormalities, including scoliosis and rhizomelic limb shortening, but less severe than CHILD syndrome; frontal bossing w/ macrocephaly; patchy scarring alopecia

93
Q

What can be seen on x-ray in Conradi-Hünermann- Happle syndrome (X-linked dominant chrondrodysplasia punctata)?

A

Epiphyseal stippling on X-ray only visible during infancy

94
Q

What is the mode of inheritance and gene involved in ichthyosis follicularis-atrichia-photophobia (IFAP) syndrome?

A

MBTPS2

XLR

95
Q

What are the primary cutaneous findings in ichthyosis follicularis-atrichia-photophobia (IFAP) syndrome?

A

Erythroderma, scaling, and follicular hyperkeratosis; generalized alopecia, including eyebrows and eyelashes

96
Q

Non-cutaneous findings in Ichthyosis follicularis-atrichia- photophobia (IFAP) syndrome?

A

Growth retardation and microcephaly; corneal opacities and ulcerations; photophobia; vascularizing keratitis; variable hearing loss; nail dystrophy; variable intellectual impairment, developmental delay, seizures, and structural CNS anomalies; genitourinary anomalies and skeletal anomalies

97
Q

Histologic features of Ichthyosis follicularis-atrichia- photophobia (IFAP) syndrome?

A

Follicular plugging and hypoplastic pilosebaceous structures

DERM (09) Genodermatoses (13 decks)

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