Dog have a common behavior like biting its tail, scooting or rubbing its bottom in the ground and it is nearly always due to anal grand problems. The well liked notion that worm infestation is the primary reason of irritation around the anus is generally speculative, but if the sign is caused by worms, segments of worm can be seen, like grains or rice, around the anus of your dog.
The anal glands is situated on either side of the anus, should be empty every time stool are passed, depositing their 
contents on the stool as a scent marker. The scent marker is useful to the wild or wandering dogs, but is largely obsolete for the household pet. High fiber diet can add bulk to the stool and may serve to make the anal gland empty more regularly.
Anal glands that become congested with stool and which are not empted by hand may be infected with fungus and bacteria, causing an abscess which can burst causing a foul smelling wound. Fungal infection in the anus can be very annoying and itching which can lead to more injury by scratching. These conditions can be prevented by having the anal glands emptied periodically at the veterinary hospital or clinic. In skilled hands this service is swiftly performed and needs no anesthetic. Surgical removal of the anal gland can be performed if the troubles persist.
Other conditions that may show these signs are:
- Anal furunculosis – Is a sore skin in the region of the anus with open wounds with pus discharge; the cause of origin is vividly unknown may is highly possibly due to a poor response of immune system or somewhat related to auto immune diseases.
- Anal adenoma – Lumps (benign tumor) around the anus that become ulcerated and raw through pressure, licking and contact with the ground as a result of scooting and rubbing its bottom.
Having these kinds of sign can be very lethal so seek veterinary advice at once especially if the area is unlikely to heal at once.