Pyoderma – how does a bacterial skin disease develop?

Skin diseases are one of the most common reasons for visits to the vet, alongside gastrointestinal disorders. Pyoderma refers to purulent infections of the skin caused by various bacteria. In healthy animals, the skin provides good protection against infections through various defense mechanisms. There is a balance between the normal microflora of bacteria, yeasts, and parasites on the one hand, and the formation and breakdown of skin cells and their waste products on the other. The microflora feeds on the waste products of the skin and at the same time prevents the colonization of infectious germs.

INHALT
Causes, classification, and development Symptoms Diagnosis Treatment Forecast Prophylaxis
Causes, classification, and development

Various factors can disrupt this balance, reducing the skin's barrier function and weakening the immune system, allowing pathogenic bacteria to multiply and infect the surface and deeper layers of the skin. This results in inflammation. Staphylococcal infections are by far the most common, but other pathogens can also cause pyoderma. The condition is not contagious between animals.

The following factors can promote the development of pyoderma:

  • Skin folds, thin layers of horny skin, or increased moisture loss from the skin
  • High temperature and humidity
  • Parasitic underlying diseases (mange, demodicosis, and others)
  • Allergic diseases (flea bite allergy, food allergy, atopy, and others)
  • Injuries

A distinction is made between primary and secondary pyoderma. While primary pyoderma is an infection of the skin without a predisposing disease and usually involves only one germ, secondary pyoderma, which is much more common, is caused by the infection of pre-damaged or diseased skin, usually with several germs.

In terms of the layers of skin affected, pyoderma can also be divided into superficial and deep pyoderma. Superficial pyoderma only affects the upper layer of skin and does not affect the general condition of the animal. It usually heals within a short time without complications. Superficial pyoderma includes, for example, "hot spots" (sudden, round, purulent, weeping, bright red, and painful areas of skin) that often occur in dogs with long or thick hair, or puppy pyoderma (pustules and skin irritation on hairless areas of the body).

Healthy skin diagram
1 Epidermis | 2 Basal membrane | 3 Dermis | 4 Subcutaneous tissue | 5 Hair shaft | 6 Hair follicle | 7 Sebaceous gland | 8 Hair muscle | 9 Hair root | 10 Hair papilla | 11 Blood vessels (blue/red)
Symptoms

Classic symptoms of pyoderma include redness, pustules (pus-filled blisters), papules (round, red bumps without pus), scaling and crusting, skin discoloration, and itching. These skin changes can occur anywhere on the body, but are more common in areas with less hair, such as the armpits or inner thighs.

Severe itching leads to increased scratching and rubbing, which can quickly cause superficial pyoderma to develop into deep pyoderma. All bacterial skin diseases should therefore always be taken seriously, examined by a veterinarian, and treated consistently.

Pyoderma in dogs
1 Skin redness | 2 Skin discoloration | 3 Hot spots
Diagnosis

Since most pyodermas are secondary diseases, the veterinarian's first task is to identify the underlying disease. A detailed preliminary report and a thorough clinical examination are essential for the veterinarian. If this disease is recognized and treated by the veterinarian, the skin infection can usually be successfully contained.

Based on the clinical examination, the veterinarian will make initial findings, which can be confirmed by cytology (cell examination). To do this, cells are taken from the area of skin change in various ways, stained, and examined under a microscope. This means that a diagnosis of the status of the inflammation, the bacteria involved, and the immune system's response can be made during the first visit to the vet. The cytological examination does not take long, is not painful for your pet, and can therefore also be carried out to monitor further treatment.

Treatment

Depending on the extent of the disease and skin damage, local antibacterial washes are used or these are used in combination with a skin-specific antibiotic therapy. Please follow your vet's treatment recommendations, especially with regard to the duration of the therapy, as skin regeneration is a slow process and discontinuing the medication too early can lead to a flare-up of the inflammation. Even if the visible skin changes have already disappeared, the invisible deep damage continues to heal. In severe cases, treatment can take up to eight weeks.

If triggering factors or underlying diseases have been identified, these must of course be eliminated and treated at the same time as the actual skin infection. In many cases, however, the underlying disease can only be diagnosed with certainty after the skin infection has subsided.

Regular check-ups with the veterinarian are recommended to assess the progress and success of the treatment.

Forecast

Depending on the type and extent of the disease, the chances of recovery are good. Consistent and correct cooperation from the pet owner plays a fundamental role in ensuring a good prognosis. In cases of deep pyoderma, scars may remain on the skin after healing. If the underlying disease cannot be treated or successfully treated, the prognosis is poor.

Prophylaxis

Skin infections cannot be completely prevented in our pets. However, with particularly good coat care, species-appropriate husbandry, and appropriate hygiene, especially in long-haired dogs, the risk of bacterial skin infections can be significantly reduced. This includes regular checks of the skin and coat by the pet owner and regular health checks at the vet. Suitable parasite prevention also helps to prevent the development of pyoderma.