Internal Medicine

0521779407-09 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:54

806 Ichthyosis

➣These ichthyoses generally manifest themselves at birth or very

shortly thereafter (except ichthyosis vulgaris, which has an age

of onset at 3–12 months).

Ichthyosis vulgaris

■MOST COMMON form of inherited ichthyosis

■autosomal dominant disorder that appears similar to acquired

ichthyosis

■diagnosis made by clinical findings

➣Recessive X-linked ichthyosis

■involves flexural surfaces as well as trunk and extremities

■associated with corneal opacities in adults

■tests of steroid sulfatase activity and levels of cholesterol sulfate aid

in diagnosis

➣Epidermolytic hyperkeratosis

■autosomal dominant disorder characterized by erythematous, scaly

plaques, thick ichthyotic scale, and bullae

■blistering with secondary infection is common

■skin biopsy and keratin gene studies will confirm diagnosis

➣Lamellar ichthyosis

■autosomal recessive disorder that presents as large plate-like scales

over the entire body

■presents at birth as collodion baby (i.e., child is born encased in

transparent, parchment-like membrane)

■diagnosis usually made by clinical findings, though testing for ker-

atinocyte transglutaminase-1 (TGM-1) mutations is available

➣Congenital ichthyosiform erythroderma

autosomal recessive disorder that presents at birth with collo-

dion membrane

clinically presents with widespread varying erythroderma and

fine white scale

diagnosis made by clinical appearance; testing for TGM-1

mutations (seen in some cases), as well as ALOX12B or ALOXE3

(lipoxygenase genes) mutations may be pursued

management

What to Do First

■Determine the underlying disorder. Acquired ichthyosis normally

appears after the manifestations of the disease associated with it;

therefore, acquired ichthyosis is rarely the sole manifestation of a

significant underlying disease.