Chewing himself

Question
QUESTION: Hi there
I have a 5 year old Maltichon. We just moved from GA to FL a little over a year ago.  My dog has started to bite and chew his stomach and hind legs to the point of sores.
We have tried sprays and lotions to no avail.
We took him to the vet who said probably an alergy.
Was put on specail food but no change.
I tried filter water-no change.
We lived in a rental home first when we moved here and it had st augustine grass that did not seem to bother him.
We bought a home last October and it does not have landscaped grass-more weeds and some other type of grass.
I think this is maybee the problem but not sure.
We took him to another vet, they gave him a steroid shot which helped but now starting to wear off.
They want to put him on some medicine for dogs with alergies, I can not remeber the name of it right now.
Do you have any suggestions before this rooute of drug taking?
Thanks

ANSWER: This isn't behavioral, it's definitely a reaction to something "new" in the environment.  Florida may have many more fleas than Georgia; flea allergy is common and the area the dog is chewing is the most likely to be inflamed by flea bites (skin is exposed on inner thighs and stomach).  First: examine the dog very closely using a flea comb: keep a glass of warm water with dish washing soap at hand.  Dip the flea comb into it if you come up with flea dirt (or living fleas).  If you find fleas, you'll need to have your home treated, wash ALL bedding, slipcovers, etc., vacuum THOROUGHLY (under cushions and furniture -- a real spring cleaning) every OTHER DAY for six weeks, and have your property sprayed by a professional.  Using a topical treatment (Vectra) that you obtain from the veterinarian will keep the dog free of fleas, ticks and even repel mosquitoes.  You'll have to apply it every four weeks until the fleas are obviously gone, then ask your veterinarian if you can apply it less frequently.  If the problem is NOT fleas, the dog should be tested; blood tests can determine allergy to various things (food related especially).  Rule out the easiest thing first, then resort to medication only if there's no obvious answer to this problem.  Allergies can crop up suddenly in humans (literally out of "nowhere") and dogs also.  This all may be coincidental, but if it is NOT and there's an environmental solution, that's the way to go.


---------- FOLLOW-UP ----------

QUESTION: Thank you for your response.
Just an addition to the info: we have him on flea control for ticks and fleas and also heart worms.  We have not seen any fleas on him at all and he has been on the same food since he was a puppy pretty much.
We tried the recommend vet food with no change.
The vet recommends using the medicine to see if that helps rather than doing the alergy test right now.  

Answer
I think testing is always a safer option than medication without understanding the underlying problem.  I'd be cautious of a veterinarian that prefers to medicate minus tests.  All medications have side effects and often dogs can't tell us what they're experiencing.  Food allergy can show up overnight.  A blood test will rule out celiac disease which has other serious complications as the dog (or person!) ages.  The flea/tick product you're using might also be causing a reaction and this, also, is not uncommon.  Some flea products don't totally prevent fleas and dogs that over groom remove the fleas so one doesn't see them on the dog.  If it were my dog, I would insist on tests before medication and also discuss the possibility of the flea prevention product's contribution to the dog's problem.