Bullous congenital ichthyosiform erythroderma, also known as epidermolytic ichthyosis and bullous ichthyosiform erythroderma (and, in the newly proposed naming convention of nonsyndromic epidermal differentiation disorders [nEDD], KRT1- and KRT10-nEDD-epidermolytic), is a rare congenital disorder presenting with blistering at birth and hyperkeratosis later in life. It presents in the neonatal period with erythema, blistering, and widespread areas of denuded skin. Some neonates may also have subtle hyperkeratosis, which may help to clinically distinguish it from other blistering disorders in neonates. After the neonatal period, infants have more verrucous scaling, particularly in the intertriginous areas. Blistering abates with time in many patients.

It is inherited in an autosomal dominant pattern, with a high (50%) frequency of spontaneous mutations. The defects are point mutations in KRT1 and KRT10, which code for either keratin 1 (K1) or keratin 10 (K10).

Ichthyosis hystrix is a variant of the disorder with very long "porcupine-like" spines composed of columns of stratum corneum with K1 or K10 mutations. Ichthyosis bullosa of Siemens is a variant with scaling and very superficial erosions related to genetic defects of keratin 2e, a keratin confined to the more superficial epidermal layers.

Rare patients with autosomal dominant ichthyosiform erythroderma with K1 or K10 mutations have small confetti-like macules (ichthyosis en confetti) that may increase in number with age. Frameshift mutations in the affected keratin gene are responsible for the new lesions.