Constant itching/scratching

Question
Good morning Dr. Gotthelf,

 I have an Akita mix female about 2 yrs. old who at this time of year starts scratching herself and chewing at her back legs, tail etc..my Doctor says she has allergies and gives her a shot but it only lasts a couple of weeks.
 I'm just wondering if I could use an OTC antihistimine product such as "ChlorTrimeton"-Chlopheniramine Maleate or something else like "Benadryl"??
 I ask this because I have a VERY limited income, and each Dr. visit/shot runs 55.00...please help if you can.
    Thank-you in advance for your help.
                Darryl Tibble

Answer
Antihistamines in the dog rarely do anything to stop itching.  They make the dog sleepy.  Rather than only getting a shot, you can ask your vet for tablets to follow up the shot.  I use a steroid tablet called dexamethasone after the shot.  It seems to control the itching better by giving these tablets every other or every third day.  Of course if the skin is also infected, the dog may also need antibiotics and baths.