Core Dermatology Diagnoses / CategoriesInflammatory

Ichthyosis Vulgaris

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Publish date: Posted on
Last updated: May 19, 2022

Keywords #
  • ichthyosis vulgaris
  • non-syndromic ichthyosis
  • inherited ichthyosis
  • xerosis
Diagnosis #

Ichthyosis is an umbrella term for a group of scaling disorders caused by a poorly formed skin barrier. Inherited ichthyosis can be syndromic, but is most often non-syndromic and limited to the skin.[1] Ichthyosis vulgaris (IV) is the most common non-syndromic form. IV is inherited in an autosomal dominant pattern and is caused by a filaggrin (FLG) gene mutation.[2]Filaggrin is integral in the formation of the cornified envelope, the outermost part of the epidermis that keeps moisture in and harmful microbial, physical, and chemical agents out.[3]

Key Concepts #
  • Ichthyosis is categorized into syndromic and non-syndromic.
  • Ichthyosis vulgaris (IV) is the most common form of ichthyosis.
  • Symptoms include xerosis, scaling, pruritus, eczema, keratosis pilaris, and palmoplantar hyper linearity.
  • Diagnosis can be made based on clinical presentation and a positive family history of IV.
  • The most common treatments are topical urea, alpha hydroxy acids, and salicylic acid as well as, systemic retinoids and vitamin D.
Epidemiology #

Worldwide, IV has a prevalence of 1:250-1:1000.[2] IV has no predilection for a specific ethnicity, sex, or geographic region, though the symptoms of IV are worse in cold and dry climates. IV presents in childhood and can improve with age.[2]

Clinical Features #

IV has variable penetrance and expression, thus symptoms of xerosis, scaling, pruritus, eczema, keratosis pilaris, and palmoplantar hyper linearity manifest to varying degrees.[1] Scale ranges from thin and fine to thick and rhomboid shaped. Areas most commonly affected are the back and extensor surfaces of the legs.[1] Moist areas such as the axillae and flexural surfaces are typically spared.[3] Overheating may also occur from impaired thermoregulation.

Differential Diagnoses #
  • Atopic dermatitis
  • Xerosis
  • Acquired ichthyosis
  • Sjögren-Larsson syndrome
  • Lamellar ichthyosis
Diagnostic Workup #

In most cases, clinical diagnosis is adequate and additional diagnostic testing is not necessary. If the diagnosis is not apparent on clinical exam and history, a skin biopsy can help confirm. Histology reveals orthohyperkeratosis of the stratum corneum and a decreased or absent granular layer. Electron microscopy(when available) will demonstrate absent or ‘crumbly’ keratohyaline granules and retractions in perinuclear keratin.[3]

Treatment #

There is no cure for IV so the primary goal is to hydrate skin and remove excess scale while preventing infection and irritation.[3] This is achieved with topical urea, alpha hydroxy acids, salicylic acid, and topical antibiotics if necessary. Patients with severe IV may benefit from systemic treatment with oral retinoids or vitamin D supplementation. Similar to their use in psoriasis, therapies targeting IL-17/IL-36 mediated pathways may be used for IV in the future.[4]

References #
  1. Takeichi T, Akiyama M. Inherited ichthyosis: Non-syndromic forms. The Journal of Dermatology. 2016;43(3):242-251.
  2. Hoffjan S, Stemmler S. On the role of the epidermal differentiation complex in ichthyosis vulgaris, atopic dermatitis and psoriasis. British Journal of Dermatology. 2007;157(3):441-449.
  3. Thyssen J, Godoy-Gijon E, Elias P. Ichthyosis vulgaris: the filaggrin mutation disease. British Journal of Dermatology. 2013;168(6):1155-1166.
  4. He H, Huynh T, Ibler E, et al. 495 Ichthyosis molecular fingerprinting shows profound Th17-skewing and a unique barrier gene expression pattern. Journal of Investigative Dermatology. 2017;137(5).
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