TL;DR: Flank sucking is usually a harmless self-soothing behavior, but you should consult a vet if it causes skin irritation or interferes with your dog's daily life.
What exactly is flank sucking in dogs?
Flank sucking is a repetitive, compulsive behavior where a dog takes a fold of skin from their flank—the area between the ribs and the hind leg—into their mouth and sucks or nibbles on it. Often referred to as self-nursing, this behavior is most commonly observed in Doberman Pinschers, though it can occur in any breed. It is generally considered a self-soothing mechanism that releases endorphins, helping the dog cope with stress or boredom.
Is it an emergency if my dog is sucking its flank?
The urgency level for flank sucking is Low. While it is usually a behavioral quirk rather than a medical crisis, you should schedule a veterinary visit if:
- The behavior becomes so frequent that it interferes with daily activities like eating or playing.
- The skin becomes raw, red, hairless, or infected due to constant moisture and friction.
- The dog cannot be easily redirected from the behavior.
How can a photo or video help my veterinarian with triage?
Providing your veterinarian with a clear photo or video of the behavior and the affected skin is highly beneficial for the following reasons:
- A photo allows the vet to inspect the area for signs of dermatitis or secondary infections that may not be obvious during a standard physical exam.
- A video helps the vet determine the intensity of the compulsion.
- Visuals show whether the dog can be easily distracted, which is crucial for a behavioral diagnosis.
Clinical Context (Merck Veterinary Manual)
Flank sucking in dogs, particularly Doberman Pinschers, can arise as a displacement behavior due to frustration, conflict, or high arousal, often triggered by unpredictable routines, environmental changes, insufficient outlets for normal behaviors, or chronic anxiety. Initially, redirecting the dog with alternative acceptable responses and constructive activities may resolve the issue. However, increased frequency and intensity can lead to a compulsive disorder, interfering with normal function and becoming independent of the initial stimulus, possibly involving altered serotonin transmission. Vacuum activity, where an animal is highly motivated to perform an instinctive behavior without an available outlet, may also manifest as flank sucking. When presented with such behavior, underlying medical issues should first be excluded.
Chapter: Behavioral Medicine
Source: The Merck Veterinary Manual, 11th Edition (Page 1561)