Interdigital cysts are firm, inflamed swellings in the skin between your dog’s toes. They’re common in dogs and easy to spot, but they’re often hard to cure and can be frustratingly prone to coming back. They can affect dogs of any age or breed, but are a particular problem in short-haired, allergy-prone or overweight dogs.

Interdigital cysts have multiple possible causes and often develop due to a combination of factors. They’re usually part of a wider paw skin condition called pododermatitis, where the skin between the toes becomes inflamed and sore. Interdigital cysts are painful, may cause limping, and often lead to persistent licking or chewing of the paws.

What are interdigital cysts in dogs?

Interdigital cysts form when inflammation builds up deep in the skin between your dog’s toes, often starting around damaged or blocked hair follicles. When a follicle ruptures under the skin, it triggers an intense inflammatory response, leading to pain, swelling and the characteristic red, angry appearance.

This inflammation is rarely caused by just one factor. Common underlying causes include:

• Allergic skin disease, such as atopy, food allergy or contact allergy

• Infections: bacterial, parasitic (demodex, hookworm), fungal or viral (papilloma virus)

• Foreign bodies: grass seeds, thorns or splinters (may leave a small weeping puncture)

• Endocrine (hormonal) disorders: hypothyroidism and Cushing’s disease

• Immune-mediated conditions: where the body mistakenly attacks its own skin cells (pemphigus foliaceous and drug, vaccine or infection complications)

In many dogs, a combination of these factors is involved, which is why interdigital cysts can be slow to heal and prone to coming back if the underlying cause isn’t addressed.

Symptoms of interdigital cysts in dogs

Common signs you may notice include:

• A painful swelling or lump between your dog’s toes: often red, inflamed and angry-looking 

• Limping or lameness: especially when walking  on hard ground or after exercising

• Persistent licking, chewing or biting at the paws

• Discharge (bloody, pus-like or straw-coloured) if the cyst bursts

• Hair loss and thickened skin around the affected area

• Swellings may be slow to heal or keep coming back: sometimes affect more than one paw
  

Are some dogs more at risk of interdigital cysts than others?

Any dog can develop interdigital cysts, but certain factors will increase your dog’s risk:

• Having a short or coarse coat: stiff hairs between the toes are pushed back into the skin and under its surface

• Suffering from allergic skin disease, such as atopy, food allergy, or contact allergy

• Carrying excess body weight or being obese: increases pressure on their paws

• Altered weight-bearing: due to arthritis, cruciate disease, a birth defect, or body conformation (body shape and stance)

• Having an extremely active lifestyle, especially playing on hard or rough ground

How are interdigital cysts diagnosed in dogs?

Vets can usually diagnose interdigital cysts based on the clinical history and a thorough physical examination. Further tests help identify the underlying cause(s) or complication.

• Skin test: skin scrapes, hair plucks, and skin smears

• Fine needle aspirate (FNA) and biopsy: collecting samples of the skin and cyst to examine under a microscope

• Bacterial culture and sensitivity testing: confirming the type of bacteria present and the best antibiotic for treatment

• Blood tests to assess overall health and/or the presence of hormonal disease

Identifying the cause is just as important as treating the cyst itself.

What’s the treatment for interdigital cysts?

Treatment will focus on relieving pain and infection, while also addressing the underlying problem in order to reduce the risk of recurrence.

The first step is to prevent further self-trauma (licking), using a cone collar, dressing or bootee to protect the foot. Treatment needs to tackle the symptoms, and potentially more than one underlying cause. 

• Prescription medicines: often include antibiotics, anti-inflammatories, and immunosuppressive drugs. These may be given orally (by mouth) or topically (creams and ointments).

• Surgery to look for and remove foreign bodies (i.e. thorns): requires sedation or general anaesthetic

• Surgery to remove the cyst completely: in some chronic cases

• Laser therapy: for recurrent or non-healing cysts

• Allergy management: may include immunotherapy and special diets (such as Hills Prescription Diet z/d or Derm Complete and Purina HA). 

• Parasite treatment and preventives: where mites or worms are involved

Treating only the red lump that’s visible will often simply lead to recurrence of the problem. Long-term success depends on managing the underlying disease with strict follow-up care.

How to care for interdigital cysts at home

Home care can support recovery in mild cases or alongside veterinary treatment. It won’t replace professional veterinary care.

• Prevent licking with a cone (buster) collar or boot to allow healing

• Clean paws gently, using vet-recommended antiseptic washes, mousses or wipes

• Dry paws thoroughly after walks or bathing

• Give prescribed medicines as directed at the correct time and dose, and always complete the course, even if the paw looks better

• Monitor for changes, such as increased swelling or discharge

• Schedule follow-up vet appointments to continue care and assess recovery

Resist any temptation to squeeze or pop interdigital cysts. Doing so causes pain, worsens inflammation and may delay healing.

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Tips on how to prevent interdigital cysts in dogs

Interdigital cysts can’t always be prevented, but these steps help to reduce the risk:

• Manage allergies early, with advice and support from your vet.

• Feed your dog a complete, balanced diet. Keep them slim and fit, with a good body condition score.

• Check their paws after walks to check for thorns, debris or other potential foreign bodies.

• Keep paw hair trimmed and groom regularly to prevent matting.

• Bathe paws after exposure to sand, salt or mucky conditions.

• Use regular parasite preventives.

• Take your dog for frequent routine vet checks, especially if they suffer from recurring skin problems.
  

Living with a dog with interdigital cysts

Dogs with recurring cysts need careful long-term management:

• Inspect their paws daily for any early signs of redness or irritation.

• Keep nails trimmed to reduce the pressure on their toes.

• Wash and dry your dog’s paws regularly, especially in wet or muddy conditions.

• Avoid exercising your dog on rough or abrasive surfaces during flare-ups.

• Stick to long-term allergy plans: follow your vet’s advice.

When you should be worried about interdigital cysts

Seek veterinary help urgently if your dog has:

• Severe or worsening lameness

• Swelling or pain that’s rapidly getting worse

• A strongly-smelling discharge

• Multiple paws affected

• Swollen joints or a fever

• Not shown to have significant improvement, despite treatment
  

Talk to a Joii Vet if:

• Your dog is limping, and you’re unsure why

• An interdigital cyst keeps coming back

• You need help managing long-term skin disease

• You need advice on caring for your dog’s paws at home

• You’re unsure whether a lump needs urgent attention

• You need help or advice on preventing licking or self-trauma