Lumps on Dogs

There are several reasons as to why lumps and bumps can form on dogs. These are quite common in older dogs. These lumps and bumps can be large (nodules) or small (papules). As with humans, when we detect lumps on dogs we tend to think of the big “C” word, the dreaded cancer. However, there are other reasons for lumps and bumps on dogs. These can be benign tumours, abscesses or cysts. Whatever the cause, if you detect any dog lump under skin, it is always recommended to have your dog examined by your veterinarian.

Lipomas are Common in Dogs

One of the most common causes of dog tumours is lipoma. These are benign tumours that form with the accumulation of mature fat cells. They are soft, round and develop under the skin. Lipomas can occur anywhere in the dog’s body especially under the surface of the chest and abdomen. Infiltrative lipomas grow in muscle and deeper tissue. These are as slow growing as the subcutaneous lipomas, but as they are deeper in the tissue it may cause your dog pain. These lipomas are less common than the subcutaneous lipomas however, your dog can be one of the few affected with it. Lipomas are treatable after proper diagnosis. Diagnostic tests include fine needle aspiration, cytology test or a biopsy. Treatment is often unnecessary in lipomas. However, if it is growing rapidly and is causing pain to your dog, excision may be necessary.

Hair Follicle Malformations

Hair follicle malformations that result in lumps on dogs are quite common. Most often excision is the only treatment option for these lumps. There are several types of hair follicle malformations. These include infundibular follicular cysts, isthmus catagen cysts, matrix cysts, hybrid cysts etc. The lumps associated with these hair follicle malformations can occur anywhere in the dog’s body. Although these are benign lesions, there have been reports of malignancies in very rare cases.


If your dog has lumps in the ears, this could be a result of blood clots. Hematoma is a very common blood vessel rupture that affects the ears. Dogs that have long ears are more susceptible to this than dogs that have short ears. Most often, the swelling may increase to great proportions and block the dog’s ear canal. Hematoma in your dog may not require treatment. However, it is always better for the dog, to have it aspirated. If not, the ear may change shape and resemble cauliflowers.

Sebaceous Cysts

If you notice a smooth, pink, wart-like growth on your dog’s limbs or eyelids that are no larger than 1 inch in diameter, he or she could be having a sebaceous cyst. They are very common in dogs and occur due to an obstruction of the hair follicles. These types of dog tumours are benign, non-painful and, as a result, will cause your dog no harm. However, you need to watch out for infections. If the lump is releasing a gray-white or brown discharge that has cheesy consistency, an abscess has formed, and you should take the dog to the vet. The vet will prescribe antibiotics or remove the cyst.

Cancerous Tumours

There are various cancerous tumours that can cause a dog lump under skin. These include squamous cell carcinomas, hemangiosarcoma, fibrosarcoma and mast cell tumours. Each of these cancers is malignant and will require surgery.

Lumps on dogs can develop very fast and can be painful depending on the underlying condition. Therefore, if you notice any lumps on your dog, you should not hesitate to get a vet’s diagnosis. This could save your dog’s life.