The CHILD Nevus: A Distinct Skin Disorder

Background: The CHILD syndrome is characterized by an ichthyosiform and inflammatory nevus showing a strikingly unilateral arrangement. No particular name has so far been given to this nevus, which is why this skin disorder has been described under various inappropriate terms such as epidermal nevus, inflammatory linear verrucous epidermal nevus (ILVEN), unilateral ichthyosiform erythroderma, unilateral ichthyosis or verruciform xanthoma. Objective: In order to avoid such confusion and to make it easier for clinicians to recognize this skin disease, a new name should be given to this disorder, and the diagnostic criteria should be delineated. Method: The term CHILD nevus is proposed and the distinctive clinical, histopathological and ultrastructural features of this disorder are described. Results: A comprehensive clinical and genetic comparison shows that the CHILD nevus can be distinguished from all other types of epidermal nevi by characteristic features such as ptychotropism, waxy yellowish scaling, a unique lateralization pattern showing both diffuse and linear involvement and the presence of foamy histiocytes in the papillae (‘verruciform xanthoma’). Contrasting with all other epithelial nevi, the CHILD nevus is an inherited X-linked dominant, male-lethal trait. Conclusion: This nevus represents a separate cutaneous entity. Future clinical research will probably show that the underlying gene defect often manifests itself as an isolated skin disorder. Such cases should no longer be confused with ILVEN. Recognition of this particular skin disorder is important for genetic counseling because a woman showing an isolated CHILD nevus has an increased risk of giving birth to a daughter suffering from a complex congenital disorder, the CHILD syndrome.