KID versus KED: What's in a Name

In this issue Caceres-Rios et al present an exhaustive review of the uncommon but clinically distinctive KID (keratitis, ichthyosis, deafness) syndrome and propose, on the basis of their analysis of the clinical phenotype, a change of name to KED (keratodermatous ectodermal dysplasia) syndrome. Implicit in the proposed name is a recategorization of KID syndrome as an ectodermal dysplasia. Before we actively or passively jump on the namechanging bandwagon and restructure our classification schemes, it seems reasonable to consider the implications of the proposed revision. The authors find the cutaneous phenotype inconsistent with disorders classified under the umbrella of ichthyosis because scaling is not the main clinical feature, and prefer to describe the typical changes as an erythrokeratoderma. Although they offer no definition, the term erythrokeratoderma is used in a context that seems to denote hyperkeratosis without prominent scaling, and with underlying erythema. Since ichthyoses are also characterized by hyperkeratosis, often in conjunction with erythema, the essence of the difference seems to boil down to whether visible scale is present or not. Without debating whether or not the fixed verrucous plaques so typical of KID syndrome could be considered nonscaling, is it legitimate to limit the ichthyosis appellation only to those generalized hyperkeratotic disorders that also display prominent scale? Are hyperkeratosis and scaliness reliably distinguishable from a clinical point of view? Don't they overlap at both the gross and microscopic levels?