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A group of hereditary disorders characterized by an excess accumulation of cutaneous scale, varying from very mild and asymptomatic to life threatening.
More than 20 ichthyoses exist; most are extremely rare and often part of multiorgan syndromes. The most common types are discussed here along with a brief discussion of two syndromic ichthyoses and ichthyosis affecting the newborn.
Acquired ichthyosis can be a manifestation of systemic disease, malignancy, drugs, endocrine disease, autoimmune disease, and HIV as well as other infections.
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ICHTHYOSIS VULGARIS ICD-10: Q80.0
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Characterized by excessively dry skin with fine white to gray to brown scales.
Affects extensors and torso.
Frequently associated with atopy, hyperlinear palms and soles, keratosis pilaris.
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AGE OF ONSET Three to 12 months.
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SEX Equal incidence in males and females. Autosomal dominant inheritance.
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INCIDENCE Common (1 in 250).
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Filaggrin mutation. Epidermis proliferates normally but keratin is retained with a resultant thickened stratum corneum.
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CLINICAL MANIFESTATION
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Very commonly associated with atopy. When hyperkeratosis is severe, many patients have a cosmetic concern.
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SKIN LESIONS Xerosis (dry skin) with fine, powdery scaling but also larger, firmly adherent, tacked-down scales in a fish-scale pattern (Figs. 4-1 and 4-2). Diffuse general involvement, accentuated on the shins, arms, and back, buttocks, and lateral thighs; axillae and the antecubital and popliteal fossae spared (Figs. 4-2 and 4-3). The face is usually spared but the cheeks and forehead may be involved. Keratosis pilaris is perifollicular hyperkeratosis with little, spiny hyperkeratotic follicular papules of normal skin color either grouped or disseminated, mostly on the extensor surfaces of the extremities (Fig. 4-4); in childhood, also on cheeks. The hands and feet are usually spared, but palmoplantar markings are more accentuated (hyperlinear).
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ASSOCIATED DISEASES More than 50% of individuals also have atopic dermatitis. ...