Dogs that have flea allergies will bite at the base of their tail and scratch frequently. The bite of a single flea can cause hours and days of intense itching. Many dogs have a characteristic loss or thinning of hair above the base of the tail. However if the dog is bathed or treated regularly, very little evidence of fleas may be found. Severely affected dogs may itch over their entire bodies, have generalized hair loss, and red inflamed skin.
Hot spots are often a result of flea bite allergies.
Flea bite allergy is characterized by being a seasonal allergy that is worse during peak flea times in the summer and fall. Diagnosis Diagnosis can be made by visual signs in combination with the presence of fleas or through intradermal skin testing . Intradermal skin testing is a very effective diagnostic tool for this particular allergy, although some false negative results can occur. Since many affected dogs also suffer from other allergies, many times the flea bite antigen is incorporated into a broader intradermal skin testing program. Some cats with flea allergy dermatitis do not have a positive intradermal test.