Bacterial skin diseases (pyoderma)

May be caused by infectious, inflammatory, and/or neoplastic etiologies; any condition that results in the accumulation of neutrophil secretions may be termed pyoderma. Most commonly, however, pyoderma refers to a bacterial infection of the skin. Pyoderma is common in dogs and less common in cats. Bacterial pyoderma can be a simple or complicated infection. Simple infections are those in young animals that are triggered by a one-time or simple event, such as a flea infestation. Complicated infections are recurrent and associated with underlying diseases such as allergies (flea allergy, atopic dermatitis, food allergies), internal diseases (especially endocrine diseases such as hypothyroidism or hyperadrenocorticism), seborrheic diseases ( These include follicular or sebaceous gland disease), parasitic diseases (e.g., Demodex mites), or anatomic predispositions (e.g., skin folds). Simple or complex infections may be superficial or deep-seated. Bacterial pyoderma that is limited to the epidermis and hair follicles is called superficial, while bacterial pyoderma that involves the dermis, deep dermis, or causes furuncle is called deep. Etiological classification refers to the causative organism involved in the infection (e.g., Staphylococcus, Streptococcus, etc.). Infections are superficial and secondary to various other illnesses.

Causes of Bacterial Skin Diseases

Bacterial pyoderma is usually caused by overgrowth/overexploitation of normal or transient flora. The main pathogen in dogs is Staphylococcus pseudostaphylococcus.

Normal resident bacteria in canine skin also include coagulase-negative Staphylococcus, Streptococcus, Micrococcus and Acinetobacter. Transient bacteria in canine skin include Bacillus, Corynebacterium, Escherichia coli, Proteus mirabilis, and Pseudomonas. These organisms may function as secondary pathogens, but S pseudintermedius is usually required for pathological processes. Normal resident bacteria in cat skin include Acinetobacter sp, Micrococcus sp, coagulase-negative staphylococci and alpha-hemolytic streptococci. Transient bacteria in cat skin include Alcaligenes, Bacillus, Escherichia coli, Proteus mirabilis, Pseudomonas, coagulase-positive and coagulase-negative staphylococci, and alpha-hemolytic streptococci.

The most important factor in superficial pyoderma that allows bacteria to colonize the skin surface is bacterial adhesion or "stickiness" of keratinocytes. Warm, moist areas of the skin, such as lip folds, facial folds, neck folds, axillary areas, dorsal or plantar fold areas, vulvar folds, and caudal folds, often have higher bacterial counts than other skin areas and increase Risk of infection. Pressure points, such as the elbows and hocks, are susceptible to infection, possibly from follicle irritation and rupture caused by repeated compression over time. Any skin disease that alters the normally dry, desert-like environment to a more humid environment will predispose the host to hyperdermatosis with both resident and transient bacteria.

Bacterial dermatitis symptoms:

Alopecia (hair loss) redness of the skin Vesicles or blisters: small heights on the outer layer of the skin filled with clear fluid Pustules: small heights on the outer layer of the skin filled with pus Skin and/or pigment loss of hair, dandruff, erythema, papules, epidermal folds

How to treat

The main treatment for superficial pyoderma is to use appropriate antibiotics for ≥21 days, preferably 30 days. All clinical lesions (except areas of complete regrowth of alopecia and areas of hyperpigmented resolution) should resolve at least 7 days before discontinuing antibiotics. Chronic, recurring, or deep-seated pyoderma usually takes 8-12 weeks or more to completely resolve.

Amoxicillin, penicillin and tetracycline are inappropriate choices for treating superficial or deep pyoderma as they are ineffective in 90% of cases. Fluoroquinolones should be used only based on culture and susceptibility.

Topical antibiotics may be helpful in focal superficial pyoderma. Mupirocin 2% ointment penetrates the skin well and is helpful in deep-seated pyoderma, is not absorbed systemically, has no known contact sensitization effects, and is not intended to be used as a systemic antibiotic increasing the potential for cross-resistance. It is not very effective against Gram-negative bacteria. This ointment should not be used in cats with any known or suspected history of kidney disease as this preparation contains propylene glycol. Neomycin is more likely to cause contact allergy than other topical agents and has variable efficacy against Gram-negative bacteria. Bacitracin Polymyxin B is more effective against Gram-negative bacteria than other topical antibiotics but is inactive in purulent exudates.

Attention to grooming is often overlooked in the treatment of superficial and deep pyoderma. Hair should be clipped in animals with deep pyoderma, and professional grooming is recommended in medium- and long-haired dogs with generalized superficial pyoderma. Cutting will remove excess hair, can trap debris and bacteria, and will aid in detangling. Long-haired cats often benefit from having their hair clipped.

Dogs with superficial pyoderma should be bathed 2-3 times/week for the first 2 weeks of treatment, then 1-2 times until the infection resolves. Dogs with deep-seated pyoderma may require daily hydrotherapy. Medicated shampoo should be pre-diluted 1:2 to 1:4 before application to promote lathering, dispersion and rinsing. Suitable antibacterial shampoos include benzoyl peroxide, chlorhexidine, chlorhexidine-ketoconazole, ethyl lactate, and triclosan. Shampooing removes bacteria, crusts, and scales and reduces the itching, odor, and greasiness associated with pyoderma. Clinical improvement in superficial pyoderma may not be apparent for at least 14-21 days, and recovery may not be as rapid as expected.

There is growing concern about the development of methicillin-resistant Staphylococcus aureus, and narrow-spectrum antibiotics should be used to treat pyoderma to minimize the development of resistance. Animals with recurrent bacterial pyoderma, deep pyoderma, and/or a history of extensive antibiotic use are best treated based on culture and sensitivity. Aggressive topical antimicrobial therapy can be helpful at the same time. Avoiding the use of fluoroquinolones and second- and third-generation cephalosporins as empiric therapy is important to reduce the development of multiple-lesion Staphylococcus aureus.

Recommended German Bayer malaseb medicated bath + golden point.