By the Pethocyn editorial team. Published October 31, 2026. Updated November 1, 2026. Sources are listed at the end of the article.

Post-grooming furunculosis is a deep bacterial skin infection that can follow a bath or grooming. A University of Minnesota veterinary dermatology handbook lists it among the deep forms of pyoderma in dogs [1]. In a deep pyoderma, the infection reaches below the hair follicle, usually because infected follicles have burst into the deeper skin. That bursting is what furunculosis means [1].

If your dog has painful sores, bumps or crusts after a bath or grooming, see your vet promptly.

Pyoderma means a bacterial skin infection. To read about its other forms, see pyoderma in dogs.

What deep skin infections look like

The handbook describes deep pyoderma in dogs as inflamed bumps and lumps, blood-filled blisters and bloody crusts that can wear down into open sores. Small channels, called draining tracts, can form and leak blood-tinged pus. These infections are often painful [1].

What one dog’s case showed

A case report from North Carolina State University describes one dog that became ill within a day of a bath. The dog was tired, would not eat and was in pain. It had bloody bumps, pus-filled spots, open sores that merged together, and crusts on the top and sides of the chest and on the rump [2]. This is one dog’s case.

Signs beyond the skin

A case report from Louisiana State University notes that whole-body signs are common in this condition, though they are usually mild [3]. Systemic means affecting the whole body, not only the skin. In the rare case that report describes, the infection spread through the body and the dog did not survive [3]. The handbook also notes that dogs with severe deep pyoderma can develop fever, low energy and swollen lymph nodes [1].

What may cause it

The handbook names Pseudomonas among the bacteria that can be found in deep pyoderma [1]. Researchers in Israel report that Pseudomonas aeruginosa is the bacterium found most often in the skin sores of dogs with post-grooming furunculosis [4]. They cultured 117 bottles of dog grooming products and found this bacterium in 14 of them, more often in products that had been diluted. They suggest that contaminated grooming products may set dogs up for severe skin infections such as this one [4]. In the North Carolina case, the same strain was found in the dog’s sores and in the shampoo used before the illness began [2]. These are findings from a small number of studies.

Treatment

Your vet will advise on treatment for your dog. Deep skin infections usually need tests to pick the right treatment, and a recheck before treatment stops [1].

At home, as directed by a vet:

  • do not put human or leftover medicines or skin products on your dog unless your vet says so;
  • give any treatment exactly as your vet prescribes, for as long as your vet says;
  • go back for any recheck your vet books.

When to see your vet

See your vet promptly if your dog has:

  • bloody bumps, pustules, open sores or crusts after a bath [2];
  • draining tracts or painful sores on the back [1];
  • pain, low energy or loss of appetite [2];
  • any skin change you are unsure about.

The bottom line

Post-grooming furunculosis is a deep bacterial skin infection that can follow a bath or grooming. Painful sores after grooming need a vet promptly.

This article is for general information only and does not replace advice from your veterinarian. If your dog has painful sores after a bath or grooming, see your vet.

Sources

  1. Torres SMF. Canine Pyodermas. In: Small and Large Animal Dermatology Handbook, Vol. 1, chapter 1.1. University of Minnesota, 2025. CC BY 4.0. https://open.lib.umn.edu/animaldermatology/chapter/canine-pyodermas/
  2. Tham HL, Jacob ME, Bizikova P. Molecular confirmation of shampoo as the putative source of Pseudomonas aeruginosa-induced postgrooming furunculosis in a dog. Vet Dermatol. 2016;27(4):320-e80. PMID 27237982. https://pubmed.ncbi.nlm.nih.gov/27237982/
  3. Pipe-Martin HN, Peterson TA, Langohr IM, Lane M, Fletcher JM, Gaschen F, Pucheu-Haston CM. Sepsis and multi-organ dysfunction associated with postgrooming furunculosis in a dog. Vet Dermatol. 2016;27(3):198-e49. PMID 27017964. https://pubmed.ncbi.nlm.nih.gov/27017964/
  4. Perry E, Sutton GA, Haggag L, Fleker M, Blum SE, Kaufmann R. Pseudomonas aeruginosa isolation from dog grooming products used by private owners or by professional pet grooming salons: prevalence and risk factors. Vet Dermatol. 2022;33(4):316-e73. PMID 35635240. https://pubmed.ncbi.nlm.nih.gov/35635240/