Puss-Filled Bumps on Dogs

There are many underlying conditions that can cause the formation of pustules on your dog's skin. When trying to determine the cause of the skin abnormality, it is important to take note of the size, location, color, firmness and spread of the bumps. While most skin conditions associated with pustules are easily treatable, it is important to take your dog the the vet for an evaluation, diagnosis and treatment.

  1. Folliculitis

    • Folliculitis occurs when your dog's follicles get infected and the hair becomes buried beneath the skin. An infected follicle usually starts as a small bump. However, over time the pustules may grow, rupture and discharge puss. Follicultis usually occurs in clusters and is generally localized in the on the underside of the body. If there is no underlying condition, folliculitis can usually be treated with a combination of oral and topical antibiotics. However, in many instances, folliculitis is developed as a secondary condition. Scabies, demodectic mange and seborrhea are all skin diseases that can cause folliculitis.

    Dermatitis

    • Canine dermatitis is caused by a bacterial skin infection. Two common dermatitis conditions are impetigo and acne. While impetigo is usually a surface infection, acne infections can be much deeper as excess sebum causes the pores to become clogged. Both conditions cause small pustules to form, grow, rupture and discharge puss. The pustules usually occur near the hairless parts of the abdomen and groin. Treatment usually involves topical and/or oral antibiotics.

    Abscesses

    • Abscesses are pockets of pus that lie under the dermis. If your dog develops an isolated pimple, boil or cyst, chances are that it is an abscess with no underlying condition. Large abscesses feel like a firm, fluid filled pocket under pressure. Treatment may include warm compresses, lancing the abscess and oral antibiotics.

    Ringworm

    • Ringworm, caused by a fungal infection, is a fairly common problem in dogs. The affected area will forms red, raised bump called a kerion. In some cases, it may become filled with puss as the infection grows worse. If your dog has ringworm, you may notice round patches of hair loss, scaly skin and brittle nails. Treatment for ringworm includes the application of topical anti-fungal medication.

    Fleas

    • Fleas are tiny parasites that infest the skin. Usually affecting the haunch and tail area, fleas lay eggs in your dog's hair and bite their skin. This causes intense itching and irritation. In some cases, the flea bites may become infected. If this happens, puss filled pustules may form. If you suspect that your dog has fleas, examine their fur carefully for white or black specks. These are flea eggs. Fleas can be removed using specially formulated sprays, shampoos or powders. Your vet may also prescribe an oral antibiotic to clear up the infected flea bites.