The reasons that dogs chew their anal region.
DUE TO WORMS-
If your dog is affected with tapeworm, it causes the animal to chew its back or drag its anus on the ground ,in medical terms called as scooting. Dogs affected with tape worms pass the segments of the worms through its excreta (faeces). The segments look like grains of rice and are white in color. Observe the anal region and the surrounding hairs for presence of any tape worm segments. Sometimes motile segments can also be observed along with the faeces since tapeworms are transmitted by accidental ingestion of infected flea. Observe the excreta and the anal region for segments and if you find any, treatment is by drug called Praziquantel ( available at the chemist as “Droncit” or as “Tradewinds tapeworm tabs”( over the counter and less expensive).
The dosage of tapeworm tab is based on the bodyweight of the animal— 4 pounds and less- half tab, 5-11pounds- 1 tab, and over 11 pound, 1 and half tablet.
DUE TO AFFECTIONS OF THE ANAL SAC-
Anal sacs are glands which are located in the anus of a dog and the secretions of these glands are used by the dog to mark the territory. Affections of the anal sac can cause a dog to chew its bottom. Infection, inflammation and tumors are the common affections. Look at the anal region of your dog for any swelling or redness, or any abnormal foul odour , or if it is having constipation, or straining to defecate. These are the common symptoms of anal sac affections. It is better to empty the anal glands. Anal glands are located in the 4 o clock and 8 o clock directions when viewed from behind. Use gloves and cotton and squeeze the anal region of your dog at the above mentioned places in an upward direction, take care the fluid coming out is very foul smelling. It is always better to empty the anal glands. It can be done by yourself, but if not willing go for veterinary aid.
After the anal sacs have been emptied it is better to apply some ointments. “Animax ointment” if available can be used. Apply the ointment into the anus. Or else go for any ointment that contain corticosteroids ( dexamethasone or betamethasone) and an antibiotic.
If the chewing is very severe, use tablets containing antihistaminics ( chlorpheniramine maleate or pheniramine maleate) available as “Avil”. Any antiallergics would also serve the purpose.
For immediate action boil some water and mix some soap containing antiseptics (like chlorhexidine) and use a cotton pad or cloths and apply pressure with it on the anal region after the hairs around the anus are clipped.
Finally, check the diet of your dog. It needs a good fiber diet as it is this fiber which provides bulk and helps in the easy evacuation of the anal sacs during defecation. If the diet is low in fiber such diseases are very likely. Provide enough fibrous material in the diet.