Routine hematoxylin-eosin staining of the biopsy specimen revealed compact orthokeratosis and a normal granular cell layer and dermis.
X-linked recessive ichthyosis is a manifestation of steroid sulfatase deficiency due to a deletion in the Xp22.3 region of the short arm of the X chromosome. Incidence ranges from 1 in 2000 to 1 in 6000 male births, with no racial or geographic predilection.1 Patients present with dark-brown, fish scale–like skin on the extensor surfaces; other flexures are variably spared. Severity is greater in dry conditions. Associated findings include cryptorchidism (12%-41%), increased risk of testicular cancer (independent of cryptorchidism), asymptomatic comma-shaped corneal opacities in Descemet membrane (16%-50%), and, in female carriers, failure to progress during labor (10%-58%).2- 5 Diagnosis can be made with serum lipoprotein electrophoresis, which shows a hypermobile beta fraction of the low-density lipoprotein.6 The National Registry for Ichthyosis and Related Disorders (telephone: 1-800-595-1265) provides direct measurement of plasma cholesterol sulfate levels, which are increased in X-linked recessive ichthyosis . Direct measurement of the serum steroid sulfatase activity and use of a combined polymerase chain reaction–high-performance liquid chromatography technique to demonstrate a decreased or absent gene are also available.7 Treatment involves moisturizers and mild keratolytics. Calcipotriol ointment has been useful in a few cases.8
Chronic Dark-Brown Scales. Arch Dermatol. 2001;137(11):1521-1526. doi: