You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Dogs are frequently (and cats occasionally) presented to veterinarians because they are biting or licking at their flanks or tailbase. Sometimes they cause severe damage to themselves resulting in bleeding, red raw areas with hair loss. Why do they do this ?

When a dog or cat turns around the nearest it can get to it's rear end is the base of it's tail or the flank. So, sucking or biting at the flank or tailbase might be caused by local irritation, or by something irritating anywhere in the pelvic area, or in the anal region. The animal will attack the side nearest to the irritation.

Common causes include :

• Impacted scent (anal) glands. Intense irritation can be caused by scent glands that are full. If the glands do not empty normally during defaecation the dog will often lick vigorously at the region, bite at the flanks or tailbase, and rub themselves along the ground (seen as "scooting").
• Fleas and flea hypersensitivity. Fleas often congregate around the tailbase area, and the reaction that occurs in flea hypersensitivy (allergy) involves the back. Both set up an itchiness (called pruritus) which leads to scratching and biting at the region. Affected dogs will often bite at their flanks in an attempt to reach their back or tailbase.

Less common causes are :

• Flank sucking in Doberman Pinschers - a psychogenic problem which is not fully understood
• Local irritation caused by :
  • A graze or scratch with secondary infection - eg seen in animals that jump fences and get snagged.
  • Tapeworm segments passed per rectum and stuck to the hair in the anal region.
  • Local inflammation of hair follicles (folliculitis)
  • Diseases of the rectum, anus or adjacent region (eg anal furunculosis in German Shepherd Dogs)
• Generalised irritation caused by 
  • Allergic skin disease (atopy)
  • Food allergy

Whatever the primary cause of the irritation the self-trauma creates a local area of injury with infection and so it and the underlying problem must both be treated simultaneously.

The earlier veterinary attention is obtained the sooner the progression of the condition can stopped, and relief can be provided for your pet. If the biting or sucking continues for a long time it can develop into a habit which can be very difficult to stop.

Updated October 2013