Pyoderma

Bacterial Skin Disease

Infection of the skin by bacteria is known as pyoderma, it can occur on its own, or as a result of another disease process that has altered the skin leading to encouragement of bacterial growth. By far the most common bacteria involved are the Staphylococcus species.

Different types of pyoderma can develop, superficial or deep infections, those involving the hair follicles, acne, dermatitis of the feet etc, they are briefly discussed below followed by a consideration of diagnosis and treatment.

Whenever dealing with a bacterial infection of the skin it is important to remember that most infections occur as a result of another problem. This may be parasitic, allergic, due to keratinisation or endocrine problems or indeed environmental if the animal has been exposed to any substances to which it is irritant.

Superficial Pyoderma; a mild skin infection creating a rash and possibly a mild itch, usually affects the groin, belly and below the elbows. Referred to as 'juvenile impetigo' as it tends to occurs in young dogs and pups. Will normally respond to simple topical cleaning of skin, more severe cases can be treated with antibiotics.

Bacterial Folliculitis; this is an infection of the skin caused by Staphylococcal bacteria. Most of these cases itch and a wide range of skin lesions such as rings, or pustules, scaling, crusts etc. Some animal may develop a patchy hair loss but the areas most often affected are those without much hair covering such as the belly and groin. It will often develop as a result of another underlying skin problem such as an allergy or atopy. Your veterinary surgeon may wish to carry out some tests such as bacterial culture, microscopy smears, or even skin biopsy. Treatment usually involves antibiotic therapy up to 3-6 weeks in duration, the prognosis depends on the underlying problem, if no underlying problem is present then the antibiotic course should resolve the problem.

Deep Pyoderma; various forms of this condition exist and are briefly described as follows:

Furunculosis- infected hair follicles creating inflammation which presents as focal thickened areas of skin which may have discharging sinuses.
Canine Acne- a bacterial condition usually affecting the skin surrounding the mouth, most common in young dogs and may improved as they reach maturity.
Callus Pyoderma- thickened skin develops over bony points on the limbs, most commonly over the elbow and hock, persistent trauma can lead to ulceration and secondary infection.
Cellulitis- infection develops and spreads beneath the skin into the subcutaneous tissues and surfaces as discharging tracts.
Interdigital Pyoderma-bacterial infection is one cause of paw lesions and will normally involve more than one foot. this frequently develops secondarily to other problems such as demodex or atopy.
Folliculitis- infection developing within the hair follicle, which if severe will develop into furunculosis.

Treatment of the various forms of this condition will involve prolonged courses of antibiotics often of up to 6 weeks duration.

Some cases can be resistant to initial therapy and investigation to determine the underlying cause may be required, such as attempting to culture the bacteria involved, or even biopsy of affected areas of skin for histopathological examination.

In addition to antibiotic therapy your veterinary surgeon may wish to use anti-inflammatory drugs such as prednisolone and anti-histamines. Topical treatments such as medicated shampoo may help to cure the condition or reduce the likelihood of recurrence.

One particular disease that affects young pups is a condition called juvenile cellulitis (also known as juvenile pyoderma, strangles, or head gland disease). Although staphylococci bacteria are frequently isolated it is not thought to be a bacterial disease and the response to antibiotic treatment is poor. It presents with swellings around the face and the glands throughout the body. The gland frequently become abscessed and develop a pus like discharge. Treatment with prednisolone for 2-4 weeks usually results in improvement but it should be combined with some covering antibiotic therapy. Once cleared the condition does not recur although some pups may be left with scarring.