Atopy patch testing with allergen extracts (Stallergenes, Antony, France) resulted in eczematous skin lesions for cat dander and house dust mite, suggesting a clinical relevance of the allergic sensitization (Fig 1, C). ...within 1 week after testing, progressive exacerbation of the erythema was noted (Fig 1, D). The precise role of ichthyin has not been elucidated; it has homologies to G protein-coupled receptors and magnesium transporter proteins and is proposed to be a receptor for trioxilins.3NIPAL4 mutations have been associated with generalized scaling and palmoplantar keratoderma and distinct ultrastructural features4; by contrast, erythema and atopy were observed only in some patients (see Table E4). ...we hypothesized that in our case additional genetic variants could contribute to and superimpose the clinical and morphologic picture.