Definition: monogenic hereditary diseases characterized by accumulation of scales with or without epidermal hyperproliferation or inflammation of the dermis.
Epidemiologia
- Non syndromic ichthyosis is estimated to affect more than 1 million in the US
Etymology
- Greek word ichthys, meaning "fish," due to the fish-like scaling seen in affected individuals
Apresentação clínica geral
- Xerose
- Descamação
- Por vezes eritema
Classification
- Date of onset
- Birth: congenital ichthyoses
- First few years of life: icthyosis vulgaris
- Extent
- Non-syndromic or isolated are predominantly cutaneous
- Common Ichthyosis
- Autosomal Recessive Congenital Ichthyosis (ARCI)
- 12 genes associated with ARCI
- Genes involve: lipid transport, lipid biosynthesis, fatty acid metabolism, role in assembling suprastructure (cornified envelope)
- ARCI occurs in approximately 1 in 100.000 to 300.000 live births
- Overlapping clinical features
- Genotype phenotype correlation
- Severity of the mutation correlates with severity of disease
- Treatment
- Emollients
- Keratolytics
- Topical and systemic retinoids
- Infection control
- Emerging role of biologic therapy (similar to psoriasiform disorders)
- Differential diagnosis of Collodion Membrane
- CIE (now ARCI)
- L (Lamellar - now ARCI)
- Ectodermal dysplasia
- Neutral Lipid Storage
- Self-healing collodion
- Idiopathic
- Gaucher’s (type 2)
- Harlequin (now ARCI) Hay-Well’s (scalp erosions)
- Trichothiodystrophy
- Keratinopathic Ichthyosis
- Keratin intermediate filament mutations → keratinopathies
- K1 Ichthyosis Hystrix Curth-Macklin
- K1/K10 epidermolytic ichthyosis
- K1 non-epidermolytic PPK (Unna-Thost)
- K2e Ichthyosis bullosa of Siemens
- K3/12 Corneal dystrophy of Meesmann
- K4/13 White sponge nevus of Cannon
- K5/14 Epidermolysis bullosa simplex
- K6a/16 Pachonychia congenita type 1
- K6b/17 Pachonychia congenita type 2
- K9 Epidermolytic PPK (Vorner)
- Syndromic or complex forms are those which have manifestations outside of the skin
- Hair abnormalities
- Neurologic signs
- May have fatal course
Generalidades - ARCI
Generalidades - Autosomal Recessive Congenital Ichthyosis (ARCI)
Generalidades - Keratinopathic Ichthyosis
Generalidades Syndromic Ichthyosis
- Genetic transmission
- Autosomal dominant
- Autosomal recessive
- X-linked dominant
- X-linked recessive
- Histological and ultrastructural morphology
- Molecular mechanism
- Profilaggrin deficiency
- Steroid sulfatase deficiency
- Keratinocyte transglutaminase deficiency
- Keratin intermediate filament mutations → keratinopathies
- K1 Ichthyosis Hystrix Curth-Macklin
- K1/K10 (domínio crítico) epidermolytic ichthyosis
- K1 (domínio não crítico) non-epidermolytic PPK (Unna-Thost)
- K2e Ichthyosis bullosa of Siemens
- K3/12 Corneal dystrophy of Meesmann
- K4/13 White sponge nevus of Cannon
- K5/14 Epidermolysis bullosa simplex
- K6a/16 Pachonychia congenita type 1
- K6b/17 Pachonychia congenita type 2
- K9 Epidermolytic PPK (Vorner)
Tratamento geral
- Emoliente
- Queratolítico
- Ureia é o mais usado
- Ácido salicílico pode ser usado mas tem o risco de absorção sistémica (barreira defeituosa), levando a toxicidade sistémica por salicilatos
- +/- retinoide tópico ou oral
- Controlo da infeção
- Biológicos semelhantes à psoríase
- Existe portaria que os medicamentos são gratuitos em farmácia hospitalar
P.S.
- Acquired Ichthyosis
- Paraneoplaastic: Hodgkin, lymphomas, leukemias, lung and breast carcinoma, Kaposi, sarcomas
- Steatorrhea with vitamin A malabsorption
- Malnutrition
- Drug reaction
- Systemic disease: renal failure, lupus erythematosus, sarcoidosis, leprosy, AIDS, hyperparathyroidism, hypothyroidism
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