Interdigital Cysts & ‘False Pads’ in Pugs
Article by Helen McKee (MRCVS), PDWRA Vet Advisor:
Pugs can be prone to both these conditions (which are linked), and especially if they are overweight.
Interdigital cysts (also known as follicular cysts or furuncles) are inflamed bumps or nodules located between the toes (interdigital area). These painful cysts can rupture and leak clear or blood-tinged fluid. If the cyst becomes infected, it will leak cream-coloured fluid.
Many factors contribute to the development of interdigital cysts, making them frustrating to manage.
How do interdigital cysts develop?
Interdigital cysts develop as a reaction to inflamed hair follicles between the toes. The inflamed hair follicles rupture into the surrounding tissue, creating more inflammation and swollen “cysts” that can open (ulcerate) and drain. This process is irritating and itchy, causing the dog to lick or chew at the area, which further traumatises the hair follicles, continues the cycle of inflammation, and potentially introduces infection. If not treated quickly, cellulitis and scarring may occur.
What causes interdigital cysts?
Allergy-induced paw inflammation is the most common cause of interdigital cysts. Allergic dogs often have itchiness and recurrent skin infections in other areas, such as their ears. Allergy triggers can include pollen, mites, fleas, and dietary proteins.
Other factors that increase the risk of your dog developing interdigital cysts (especially between the outside two toes) are mechanical in origin. An abnormal amount of friction in the interdigital space can cause inflammation of the hair follicles. This is more likely to occur for obese dogs who put excessive pressure on their paws or pugs that have abnormal leg conformation which alters the weight distribution on their pads as discussed below (under False Pads).
What are the signs of interdigital cysts?
If your dog has interdigital cysts, you will see raised red bumps between your dog’s toes and your dog may be licking or chewing at their feet more than usual. Your dog’s paws may also be discoloured – especially if they have a secondary infection. You may even notice small blood spots on the floor if a cyst has ruptured. Dogs who are in pain may limp or be reluctant to walk.
How is the underlying cause of interdigital cysts diagnosed?
After a complete history and physical examination of your dog, your vet may recommend testing the skin for Demodex mites, bacteria, and yeast by performing skin scrapings, hair plucks, and/or tape preps of the area.
How are interdigital cysts treated?
Treatment is aimed at controlling the underlying cause, so it typically includes allergy treatments, and anti-inflammatory medications such as steroids (prednisolone) and cyclosporine (Atopica™). Other allergy medications, including (Apoquel™) (Cytopoint™), can help control your dog’s itching but aren’t considered to be effective enough to treat the degree of inflammation involved in interdigital cysts.
Secondary infections may require long courses of antibiotics, sometimes up to 8 weeks. Topical treatments like steroid ointments and antimicrobial paw soaks (chlorhexidine also known as Hibiclens) can be very useful to manage superficial inflammation and infection.
If arthritic changes and/or obesity have promoted cyst formation, these chronic conditions need to be managed more effectively with medications and nutritional therapy. Providing protective boots and controlling the surfaces your dog walks on (soft surfaces best like grass) can help manage the disease as well.
Many cases respond well if an underlying disease is found and treated appropriately. If an underlying disease is not (or cannot be) managed well, interdigital cysts can recur more frequently, causing chronic inflammation, scarring, and pain.
False pads can also result in ‘interdigital cysts’ and can be seen in dogs where abnormal conformation (shape of dog’s legs) results in altered weight bearing on hairy interdigital skin of the paw. Over time, and this can be years, because of the resulting chronic inflammatory changes, the foot tries to form new footpads at the sites; many dogs develop interdigital ‘cysts’ above these areas in the webbing of the pads.
It tends to form on the forelimbs more due to the greater weight bearing load. Because it is conformational, it can be very difficult to manage.
Strategies include weight loss, avoidance of rough terrain (most are better on grass for example), use of little boots out on walks, use of anti-inflammatories (steroids and Atopica can both help in some cases) and in the worst cases, surgery.
Surgery is a very last route to go, and only to be considered in extreme cases of false pads as it involves fusion of toes.
Photos of a case of false pads in a PDWRA rescue pug whom Malcolm and I fostered.
Bella was grossly overweight.
Helen McKee (MRCVS)
PDWRA Vet Advisor
For more useful articles about our pug’s health & wellbeing, please see: https://pugwelfare-rescue.org.uk/pug-health/
