Chapter 9: Genodermatoses
Genodermatoses: Ichthyosis
Ichthyosis is a family of diseases that lead to dry, scaly skin. As with epidermolysis bullosa, there is a wide range of presentations for mild involvement to severe and life-threatening involvement. The mildest forms of ichthyosis are so common and mild, that they are usually only identified based on clinical examination and no further investigation is warranted. More severe ichthyosis presents at birth and rapid intervention is needed.
Types of ichthyosis include:
Ichthyosis vulgaris: Ichthyosis vulgaris is quite common and is caused by mutations in the Fillagrin gene. Patients have increased risk of atopy and present with dry skin especially over the shins. They may have associated hyperlinearity of the palms.
X-linked ichthyosis (XLI): XLI is seen only in boys and mothers are carriers. They may be born after prolonged labor, can have undescended testes, and may be found to have corneal opacities that do not affect vision. Skin changes lead to appearance of dirty brown skin with accentuation on extremities but sparing of the antecubital and popliteal fossa.
Autosomal Recessive Congenital Ichthyosis (ARCI): ARCI is uncommon and often presents with collodion membrane at birth. One form of ARCI presents with widespread erythema and fine scale. Another form of ARCI, commonly called lamellar ichthyosis, presents with large plate-like scale and may be associated with alopecia, ectropion and eclabium.
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