Diagnosing Lumps on Dogs' Skin

Lumps on dogs may be smaller (papules) or larger (nodules) and may not always be tumors, as most pet owners would think. Lumps may indicate a broad range of conditions. The appearance, additional symptoms as well as tests or biopsies may be used to diagnose lumps on dogs.


Abscesses on the surface of the skin may appear as lumps. These lumps will be caused by an accumulation of pus, due to an infection. The nodules may be larger or smaller and the dog may also have fever due to the infection. The lumps may drain and pus will come out. Antibiotics are required to remove the infection and the abscess.

Acral Lick Dermatitis

Often, dogs lick themselves due to anxiety, stress, boredom or allergies. This may result in skin trauma and wounds; you may detect lumps and lesions on the dog's skin. The cause for self licking must be identified, eliminated and the lumps will also go away. In extreme cases, the dog will receive a lamp shade collar to prevent self licking.


Allergies may be developed to a wide range of factors including antibiotics on the skin, contact with different materials such as iron, copper, nickel, rubber or wool and other chemicals. Lumps and bumps may develop as a result of allergies; the dog may also have blisters, red skin and hair loss. The allergen must be identified and possibly eliminated. The dog may also receive antihistamines and steroids.


Lumps on the skin of the dog may be cysts. There are several types of cysts that may be present in dogs:

  • Follicular cysts
  • Sebaceous gland cysts
  • Apocrine sweat gland cyst
  • Epidermal inclusion cysts

The cysts will be round, smooth and may cause hair loss in the area. The cysts are typically made up of liquid or soft skin tissue.

Cancerous Tumors

Lumps on the skin of the dog may indicate cancerous tumors; these tumors may be of several types and these may be established by performing a biopsy:

  • Basal cell tumors, filled with liquid and hyperpigmented
  • Fibrosarcoma, a solid growth, with an irregular shape that may ulcerate
  • Lymphoma, causes ulcers and itchiness
  • Mast cell tumors, nodules with various shapes, sizes and colors
  • Melanoma, a dark colored nodule that will ulcerate
  • Squamous cell carcinoma, cauliflower shaped nodules or crusted ulcers


A granuloma can be caused by an infection or a foreign material. The granuloma is a firm nodule, may be smaller or larger and may ulcerate.

Canine Acne

Canine acne may be present on the facial area and this may be felt as lumps on the chin and lips. The papules may drain and can be treated with antibiotics.

Benign Growths

Not all tumors are cancerous; there are a number of growths that may occur on canines:

  • Lipoma, which is an accumulation of fatty tissues
  • Nevi, lesions that are firm and are more common on the head and neck
  • Warts, also known as cutaneous papilloma, caused by viruses, have a cauliflower appearance