NC mice, which were established as an inbred strain on the background of Japanese fancy mice, develop an atopic dermatitis(AD)-like skin lesion with IgE  hyperproduction (NC dermatitis) when bred in conventional conditions.  This disease serves as a model for human AD.  Various factors have been speculated to be involved in the induction of NC dermatitis, but none have been clearly implicated.  Interestingly, experimental infestation of Myobia musculi or Myocoptes musculinus induces dermatitis with hyperproduction of IgE in NC mice, which is clinically and pathologically similar to NC dermatitis.  The eradication of mites reduces serum IgE level and improves the dermatitis.  These data strongly suggest that mite antigen is one of the factors regulating the onset of AD-like skin lesion in NC mice.  A further understanding of the relationship of mite antigen to NC dermatitis will elucidate the pathogenesis of human AD and identify effective treatments.