Benadryl has been useful in treating a number of symptoms in dogs, including insect bites, car sickness, and allergies. However, this medication had originally been designed for human consumption, so its dosage should be adjusted to suit your dog. The recommended amount to give your dog is 1 milligram of the medication per pound of body weight, and should not be administered less that 8 hours apart. For more information about Benadryl use on dogs, you can visit this site: http://www.vetinfo.com/dog-benadyrl-stop-itching.html
Antihistamines like Benadryl can be given to dog safely to relieve itching, but it is recommended to check first with a veterinarian the proper dosage to be given. Regularly bathing your dog using cool water and applying baking soda or Epsom salts are also useful to temporarily relieve itchiness in dogs. Here’s the link for more information: http://www.dogbreedinfo.com/itchydog.htm.