Allergens from House Dust and Storage Mites

House dust mites are among the most important allergy triggers worldwide. While mites of the genus Dermatophagoides occur almost worldwide, the tropical mite Blomia tropicalis and storage mites are only of importance for certain areas or groups of people. The most important allergens of Dermatophagoides pteronyssinus are Der p 1, Der p 2, and Der p 23 with immunoglobulin E (IgE)-binding frequencies of more than 70% and high allergenic activity. Also of importance are Der p 5, Der p 7, and Der p 21, which have IgE-binding frequencies of about 30%. According to the current state of knowledge, these six allergens are the allergens of clinical relevance which are also required for diagnosis and immunotherapy with individual components.