Dust mites are microscopic living organisms that are impossible to see with the naked eye. It is necessary to use a microscope to detect them. They fall into the arthropod-arachnoid category. Dermatophagoides Pteronyssinus and Dermatophagoides Farina are the most important and well-known species in Europe. Mites multiply mainly in autumn but in springtime as well. The signs of their existence are less in the summer due to the fact that we remove objects like blankets, carpets and we ventilate the rooms of the house more frequently.