In modern conditions, the percentage of allergic diseases increases every year. A sufficient number of studies have been devoted to the study of various aspects of the pathology under consideration in small pets, but its solution will contribute to a comfortable life for the patient. According to the conducted research, it was found that among dermatological diseases, there were such as allergic: in cats 22.2%, in dogs 15.5%; parasitic in cats 13.3%, in dogs 10.5%; fungal in cats 6.3%, in dogs 7.2%, bacterial in cats 5.8%, in dogs 6.4%; thermal in cats 5.2%, in dogs 2.3%, chemical in cats 5.3%, in dogs 2.2%. Flea allergic dermatitis is a hypersensitivity reaction to one or more components of fleas, especially to allergens contained in their saliva. Flea dermatitis is most often recorded in late summer, which corresponds to the peak of flea numbers. The purpose of flea control is to eliminate them on pets, eliminate existing contamination in the environment and prevent re-infection. The main symptoms indicating allergic flea dermatitis: severe itching; numerous wounds due to scratching; hair falling out, the appearance of bald patches on the animal's body, ulcers covered with crusts; lack of appetite, vomiting; inappropriate behavior, irritability. When diagnosing allergic flea dermatitis, a number of factors were taken into account, including anamnesis, clinical signs, results of a wet test for the presence of fleas or their excrement, cytology of skin scraping, as well as the exclusion of other causes of dermatological diseases including atopic dermatitis and food allergies. The clinical signs of allergic flea dermatitis are variable and depend on the duration of the disease, as well as the degree of hypersensitivity and the consequences of previous or current treatment.