A 60-year-old man requests consultation for severely dry skin. The dry skin has been present for as long as he can remember, and several other family members are similarly afflicted. Examination reveals marked xerosis with a fish scale pattern of both lower legs.
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Ichthyosis vulgaris is an autosomal dominant, genetically inherited disorder that is estimated to affect 1 in 250 individuals. The condition typically presents early in childhood and tends to improve with age. It is often seen in association with atopic dermatitis.1
The classic fish skin stigmata of ichthyosis vulgaris is the result of dysregulated keratinization in the skin.1 This abnormal keratinization is associated with mutations in more than 50 genes encoding for proteins and enzymes involved in integral cellular functions, such as skin barrier homeostasis.2 Abnormalities in these cellular functions lead to epidermal hyperplasia with the formation of excess stratum corneum and the characteristic scaly skin.3 Individuals with ichthyosis have diminished or absent profilaggrin, which is synthesized in the granular layer of the epidermis and is a major component of keratohyalin granules.4,5
Diagnosis of ichthyosis vulgaris is based on the cutaneous findings and family history. The condition is chronic in nature and often requires continuous therapy. Topical alpha-hydroxy acids, such as ammonium lactate, are the mainstay of treatment, and these work by decreasing corneocyte adhesion in the outer stratum corneum.
Dr Schleicher is director of the DermDox Center for Dermatology, as well as an associate professor of medicine at the Commonwealth Medical College and a Clinical Instructor of dermatology at Arcadia University and Kings College.
- Habif TP. Ichthyosis vulgaris. In: Clinical Dermatology. 5th ed. Philadelphia: Elsevier; 2010: 167.
- Oji V, Tadini G, Akiyama M, Blanchet Bardon C, et al. Revised nomenclature and classification of inherited ichthyoses: results of the First Ichthyosis Consensus Conference in Sorèze 2009. J Am Acad Dermatol. 2010;63:607-641.
- Schmuth M, Gruber R, Elias PM, Williams ML. Ichthyosis update: towards a function-driven model of pathogenesis of the disorders of cornification and the role of corneocyte proteins in these disorders. Adv Dermatol. 2007;23:231-256.
- Winge MC, Hoppe T, Berne B, Vahlquist A, et al. Filaggrin genotype determines functional and molecular alterations in skin of patients with atopic dermatitis and ichthyosis vulgaris. PLoS One. 2011;6:e28254.
- Vahlquist A, Fischer J, Törmä H. Inherited nonsyndromic ichthyoses: an update on pathophysiology, diagnosis and treatment. Am J Clin Dermatol. 2018;19:51-66.