Metatarsal and Metacarpal Fistulas in Dogs

Metatarsal and metacarpal fistulas are sometimes immune mediated diseases which are more commonly found in specific breeds like German Shepherds and Weimaraners, and sometimes seem to favor the male gender in these breeds.  The term immune mediated refers to diseases or conditions which stem from various activities of the immune system, usually indicating inflammation of some sort, which result in areas of painful, oozing and inflamed areas on the paws of the canine.

Metatarsal and metacarpal fistulas in dogs can be defined as a dermatological condition which causes swelling and oozing on the backs of the paws in the metatarsal and metacarpal areas of either the front or back paws (or both) of dogs as well as cats.

The symptoms of metatarsal and metacarpal fistulas in dogs are mainly those relating to dermatological (skin) with some lameness, such as:

• Excessive licking of the paws (either both front or both rear paws)
• Swelling of tissue around the metatarsal and metacarpal pads of the paw
• Oozing or drainage of bloody or pus-like material from those areas
• Red, raw and inflamed skin in those areas
• Sometimes can be painful with manipulation or walking

Types  

While sometimes the etiology of these fistulas remain unknown despite the best diagnostic efforts, there are several ways that these deep infected tracts are commonly found:

• Foreign body related
• Neoplasia related
• Food allergy related
• Parasitic related
• Drug related
• Immune mediated  
• Allergy related
• Bacterial infections of various types
• Breed predisposition

Many of these fistulas resemble and have similar characteristics to various types of pododermatitis, and various types of dermatitis found on the skin of canines.

The first thing to note about this condition is that it is not a common malady found among breeds. The causes of metatarsal and metacarpal fistulas in dogs can be challenging to determine.  Here are some of the possible causes of these fistulas:

• Foreign body penetration or other trauma
• Infections of various types (bacterial, fungal)
• Allergies (including food)
• Parasitic presence
• Immune mediated (caused by activities of the immune system)
• Neoplasia or cancers
• Some dog breeds seem to be predisposed to formation of them
• Idiopathic - no known cause

Your veterinary professional will need your input for the history of the injury or condition, the dietary history as well as physical activity history.  He will do a physical examination and will likely need blood and tissue samples for laboratory evaluation and assessment. Microscopic examination of the material oozing from the fistula will provide additional information to augment the laboratory evaluation. Biopsies will also provide clearer information in the diagnostic process.  There are times, regardless of the diagnostic technology available, that no definitive diagnosis for the root cause can be obtained.  

In these cases, treatment options will be focused on the treatment of symptoms and clinical signs found in the examination. Frequently, when the root cause is considered “idiopathic” (of unknown cause), treatment options may involve many months if not lifelong treatment to keep the condition under control.  A treatment plan will be developed by your veterinary profession based on what is found in this diagnostic process.

Treatment options for metatarsal and metacarpal fistulas are related to the root cause of the disease.  

• If the cause is determined to be bacterial, oral or injectable antibiotic medications are utilized  
• If the cause is foreign body, then steps will be required to remove the foreign body with appropriate antibiotic treatment being utilized after the surgical removal of the foreign body for a specific period of time  
• If the cause is found to be trauma, surgical repair of the damages will be required with appropriate antibiotic medication being administered after surgery  
• If the cause is food related, dietary changes may be required
• If the cause is parasitic in nature, the parasite will be appropriately treated  
• If the cause is immune mediated, inflammation will be prevalent and it will need to be treated now and monitored over time as the condition will likely repeat itself if the root cause is not treated; in some cases, steroids, as well as antibiotics, may be called for in the treatment plan in any of these scenarios

You should expect that, with appropriate and timely treatment, your beloved canine family member’s condition will improve and he should return to some degree of normalcy.  If the condition was a result of a behavioral issue, which is sometimes the case as well as those causes noted above, then expect to make some changes in various routines in which your pet is involved.  It would be prudent to expect to be required to monitor the paws of your pet, perhaps for the rest of his life, in an attempt to catch the condition as early as possible for medical intervention when and if it repeats itself.  As always, be prepared to administer as much of the three A’s (attention, affirmation and affection) as needed and when needed both while your pet is healing as well as for the rest of his life.