Lamellar ichthyosis and non-bullous ichthyosiform erythroderma
Understandably, these rare conditions have often been confused in the past. Both may be inherited as an autosomal recessive trait, and in both the skin changes at birth are those of a collodion baby . Later the two conditions can be distinguished by the finer scaling and more obvious redness of non-bullous ichthyosiform erythroderma. Both last for life and are sufficiently disfiguring for the long-term use of acitretin to be justifiable (Formulary 2). Lamellar ichthyosis shows genetic heterogeneity: the most severe type is caused by mutations in the gene for keratinocyte transglutaminase, an enzyme that cross-links the cornified cell envelope, lying on chromosome 14q11.2.