A case of dermatitis associated to macronyssid mites in a female patient from Tuetal Norte, an rural town in the province of Alajuela, Costa Rica is described. The patient showed an intense and generalized rash with constant pruritus, and the other family members presented similar manifestations. The patient described "small animals" walking over her body and on the house walls. A sample of these organisms was cleared and mounted for microscopic examination. The analysis of the preparations revealed mites belonging to the family Macronyssidae. Treatment was performed with Tetmosol® soap, Eurax® lotion and Atarax®. The application of an acaricid solution in the house was recommended. The patient was cured 10 days after the beginning of treatment.
