Using the terminology for Dermatophagoides pteronyssinus, IgE responses to house dust mites have been shown to be mostly directed to the serodominant Der p 1, 2 and 23 allergen components with mid -tier responses to Der p 4, 5, 7 and 21 that are made by 30–50% of subjects with titers proportional to those of the serodominant specificities. This pattern can be seen to evolve in childhood and although responses to minor allergens appear to contribute little to the total IgE they are at least markers for a greater propensity to develop disease. While Der p 23 is a component that induces prevalent IgE responses, sometimes in the absence of responses to Der p 1and 2, not all studies have found high titers so further investigation is needed. From limited knowledge adult onset IgE responses might have a different pattern that is not so centered on Der p 1 and 2. Responses that induce under 3.5 IU/ml of IgE antibody are not usually associated with disease and should be examined for cross reactivity expected from IgE responses to other allergens and antigens of infectious agents. Scabies that has 40% endemicity in some regions and is spread by immigration can give rise to high-titer binding that can be recognized by component resolved diagnosis. Recent studies with synthetic peptides representing allergens and non-allergenic HDM proteins now offer new research avenues on HDM induced immune responses, including the ability to use peptides representing the serodominant allergens as defined reagents for long overdue reproducible T-cell investigations.