Nummular Eczema, Discoid eczema, Atopic dermatitis, Contact allergy, Pediatric case, Etiopathogenesis. Root cause of disease Extremely dry skin is dehydrated skin Researchers believe that skin dryness plays a role in causing nummular eczema. You can develop excessively dry skin during winter when the humidity in the air drops or when taking a medication that can dry out…