Cat Skin Problems Indicated by Bumps

Bumps on the feline skin may be smaller (known as papules) or larger (nodules). Often these papules and nodules indicate cat skin problems. Most often, people associate bumps with cancer, but there are also other conditions that may cause the occurrence of bumps including abscesses, dermatitis, cysts, insect bites, acne or negative reactions to medications.


An abscess may be caused by an infection and pus will accumulate under the skin. The cat may also have additional symptoms such as fever, lack of appetite, foul odor in the area or thick yellow or creamy white discharges.

Contact Dermatitis

Certain materials and ointments may irritate the skin of the cat, so bumps may occur. Common ointments that cause bumps include antibiotics and steroid creams. Materials that may irritate felines include nickel, copper, iron, wool, plastic or rubber. Also, if the cat comes in contact with certain chemicals such as dyes or irritant plants such as poison ivy, he may also develop contact dermatitis.

In addition to the bumps, the cat may also display redness, itchiness and hair loss.

Cysts in Cats

Cats may develop different types of cysts including:

  • Sweat gland cysts, which appear as bumps filled with water, sometimes bluish in color
  • Follicular cysts also known as sebaceous cysts, which contain a yellow or gray substance

Cysts are harmless and may be removed surgically or may go away without treatment.

Insect Bites

Insects such as ants, bees, ticks, mosquitoes or fleas may bite felines and certain cats will develop bumps in the bite area.

If the cat is severely affected by the bite (gets very swollen), he may require an epinephrine shot. Otherwise, steroid ointments can be used to heal the bites.

Feline Acne

The causes of feline acne are not known but the condition may be linked to hormonal problems or underlying infections; certain felines are more prone to acne.

The acne can occur as comedones which can turn into small nodules or bumps.

Once the problem is detected, the cat can receive a treatment with ointments and special formula shampoos.

Negative Reactions to Medications

More sensitive felines may develop negative reactions to drugs or injections. The most common irritants include antibiotics (especially penicillin), sulfonamides or cephalosporins.

The reaction should occur 2 weeks within the administration of the culprit medication.

Tumors in Cats

Tumors may be either benign or malignant. Among the benign tumors, the basal cell tumors are the most frequent. These tumors appear as small nodules that are filled with liquid; in some cases these tumors are hyperpigmented.

The malignant tumors may be of different types: fibrosarcomas, melanomas, squamous cell carcinomas, lymphomas or mast cell tumors. These tumors will cause bumps of different sizes and colors (i.e. melanomas are dark in color). The malignant tumors are aggressive and will get larger.

Other less common conditions that may cause bumps in cats include fungi (i.e. coccidia or Sporothrix schenckii), hookworms and bacterial infections (i.e. Pyoderma-deep).

Take your pet for a veterinary consult to determine the skin problem and get appropriate treatment.