Allergic dermatoses represent the most observed dermatological complaints in most health facilities in the Congo, particularly in the Brazzaville hospital and university center. Dermatological and entomological surveys were conducted in 4 districts covering 40 dwellings for 212 people visited. The study was conducted over a year integrating the rainy season and the dry season. Dix dwellings were chosen in each of the five neighborhoods of each district. The collection of the specimens in the houses was consecutive to the brushings of the sofas, the carpets, the soft toys, the carpets but also after display of a cloth under the beds. Other specimens came from house dust. In the dwellings selected, the temperature and humidity were systematically recorded. The results show that three (3) types of allergic dermatosesare observed: popular urticaria, eczema and scabies. It appeared that popular urticaria represents the highest prevalence with 86% of cases mainly in children whose age is between 3 and 9 years. On the other hand, 727 specimens of arthropods incriminated in the occurrence of dermatoses in the houses are mites belonging to the species Dermatophagoides pteronyssinus, D. farinae two of the family of pyroglyphidae and Ixodes_ricinus of the family Ixodidae. Abundance of harvested arthropods was observed at 26.26 ° C and 70.14% RH on average.