Ichthyoses--Part 2: Congenital ichthyoses.

Congenital ichthyoses are a group of genetic disorders with defective cornification, clinically characterized by scaling of the skin. Additionally, distinctive cutaneous inflammation can often be observed. For most of the patients these diseases lead to a significant restriction in quality of life. The diagnostic hallmarks are discussed. The diagnostic criteria include clinical and histological findings, often enhanced or confirmed by specialized tests. Because many of the congenital ichthyoses are extremely rare, their accurate diagnosis is often carried out in specialized centers. After discussing the vulgar ichthyoses as well as the diagnostic and therapeutic options in part one, in this second part we review congenital ichthyoses both with and without associated symptoms, focusing on the common genetic changes and their clinical phenotype. Specific therapies are still not available for most of these disorders. The use of different topical agents (e. g. urea, retinoids and salicylic acid) and baths followed by mechanical keratolysis (sometimes in combination with systemic retinoids) reduce skin symptoms. Patients with uncommon congenital ichthyoses often benefit from interdisciplinary management which involves specialized dermatological centers.