BACTERIAL SKIN DISEASES : SUPERFICIAL STAPHYLOCOCCAL PYODERMA
- At a glance
- WHAT DOES IT LOOK LIKE?
- WHAT ELSE LOOKS LIKE THIS?
- HOW DO I DIAGNOSE IT?
- HOW DO I MANAGE IT?
- COMMENTS
At a glance?
- A superficial bacterial infection of the epidermis and hair follicle, usually secondary to allergic, parasitic, endocrine, autoimmune, conformational or keratinization disorders
- Staphylococcus pseudintermedius is the most common causative organism. S. schleiferi and S. aureus are less common
- Staphylococcal methicillin resistance can occur, especially in patients with recurrent infections and after multiple courses of antibiotics
- Common in dogs; rare in cats
What does it look like?
- Can occur in any breed of dog but is more commonly diagnosed in breeds prone to atopic dermatitis
- Clinical signs include erythema, pustule, papule, crust, scaling, epidermal collarettes, and alopecia; cats most commonly present with multiple crusted papules ("miliary dermatitis") or erosive plaques
- Short-coated breeds often have "moth-eaten" patchy alopecia on the trunk with subtle circular to semi-circular scales and epidermal collarettes
- Most commonly affected areas in dogs are axillae, groin, ventral neck, ventral abdomen, interdigital spaces; in cats are the face, neck and ventrum
- The full extent of skin lesions may be difficult to appreciate until the hair is clipped
- Pruritus ranges from absent to severe
What else looks like this?
- Demodicosis
- Sarcoptic mange
- Dermatophytosis
- Pemphigus foliaceus
- Drug eruption
- Sebaceous adenitis
How do I diagnose it?
- Skin scrapings to rule-out Demodex, fungal culture to rule-out dermatophytosis
- Skin cytology: impression smears on pustule, papule, crust or epidermal collarettes
- For true infection should see intracellular bacterial cocci and neutrophils; overcolonization shows increased numbers of cocci with few to no neutrophils
- Bacterial culture/susceptibility testing in cases with a history of past antibiotic use, in non-responsive cases , therapy dogs with pyoderma, or to rule-out methicillin resistance
- Skin biopsy for dermatohistopathology to rule-out other diseases; findings in cases of superficial pyoderma may include subcorneal pustule, folliculitis, and perfolliculitis; bacteria may be seen in crust or follicular keratin
How do I manage it?
Systemic antibiotics- see Table 1
- Choose empirically based on predicted efficacy, safety and likelihood of pet owner compliance
- Systemic antibiotics should be selected based on results of culture and susceptibility testing in patients with infections that do not resolve with empirical therapy, in chronic or recurrent infections, or with a history of past antibiotic use
- Antibiotics should be given for at least 14 days or until clinical signs of pyoderma have completely resolved, but not longer than necessary to decrease selection of resistant bacteria
- Combine with frequent antibacterial topical therapy
Table 1. Antibiotics Useful for Treatment of Superficial Staphylococcal Pyoderma | ||
---|---|---|
DRUG | DOSAGE(mg/kg) | DOSE INTERVAL |
amoxicillin trihydrate / clavulanate potassium | 12.5 | q 12 hours |
cephalexin | 22 - 30 | q 8-12 hours |
cefovecin sodium | 8 | subcutaneous, q 14 d |
cefpodoxime | 5-10 | q 24 hours |
chloramphenicol | 40 - 50 | q 8 hours |
clindamycin | 5.5 - 11 | q 12 hours |
doxycycline | 5 10 |
q 12 hours q 24 hours |
enrofloxacin | 5 - 20 | q 24 hours |
erythromycin[MH1] | 10[MH2] -20 | q 8 hours |
marbofloxacin | 2.75 – 5.5 | q 24 hours |
orbifloxacin | 2.5 | q 24 hours |
trimethoprim / sulfadiazine | 15-30 | q 12 hours |
- Frequent bathing 2-3 times weekly initially, then weekly to prevent recurrence.
Use antibacterial shampoos, especially chlorhexidine or benzoyl peroxide- based products: 10 minutes of contact time before rinsing - How to give a medicated bath (.pdf)
- Consider chlorhexidine sprays and wipes 1-3 times daily on affected areas in between baths; nisin wipes are an alternative for animals that react to chlorhexidine
- 0.5% sodium hypochlorite spray or soaks may also be helpful, especially in resistant cases
- Topical fatty acid or oligosaccharide-containing sprays and spot-on's may help restore the skin barrier and reduce bacterial colonization
- Localized lesions may be treated with topical antibacterial creams or ointments (e.g., mupirocin, silver sulfadiazine, or sodium fusidate)
- Staphage lysate® (Delmont Labs) can be used as an adjunct treatment to stimulate the dog's immune system against the Staphylococcus bacterium and may result in fewer episodes of recurrence
Tips
- Identify and develop plan to manage the underlying cause; control flare factors such as underlying atopic dermatitis, food allergy and flea allergy
- Incorporate aggressive topical therapy into initial and long-term treatment plans
- Perform a bacterial culture and susceptibility testing in patients that do not respond to empirical therapy or with a history of previous antibiotic use
- Give client education on the importance of compliance and the need for a diagnostic work up in recurrent or non-responsive cases
- Focus on treatment plans that are feasible for the pet owner
- Consider referral to a local dermatologist for resistant or recurrent cases
- www.wormsandgermsblog.com for infection control information and client hand-outs on methicillin resistant Staphylococcus infections
- www.mrsainanimals.com/BSAVA.html for information on methicillin resistant Staphylococcus infections
- Hand-out on infection control for veterinary hospitals
- Miller WH, Griffin CE. Campbell k. eds. Muller and Kirk’s Small Animal Dermatology 7th ed. Saunders, 2013: 125. 188-207
- Veterinary Clinical Advisor. Dogs and Cats. Cote.E. 2nd ed. Mosby. 2011: 951-953
abscess
A discrete swelling containing purulent material, typically in the subcutis
alopecia
Absence of hair from areas where it is normally present; may be due to folliculitis, abnormal follicle cycling, or self-trauma
alopecia (“moth-eaten”)
well-circumscribed, circular, patchy to coalescing alopecia, often associated with folliculitis
angioedema
Regional subcutaneous edema
annular
Ring-like arrangement of lesions
atrophy
Thinning of the skin or other tissues
bulla
Fluid-filled elevation of epidermis, >1cm
hemorrhagic bullae
Blood-filled elevation of epidermis, >1cm
comedo
dilated hair follicle filled with keratin, sebum
crust
Dried exudate and keratinous debris on skin surface
cyst
Nodule that is epithelial-lined and contains fluid or solid material.
depigmentation
Extensive loss of pigment
ecchymoses
Patches due to hemorrhage >1cm
epidermal collarettes
Circular scale or crust with erythema, associated with folliculitis or ruptured pustules or vesicles
erosion
Defect in epidermis that does not penetrate basement membrane. Histopathology may be needed to differentiate from ulcer.
erythema
Red appearance of skin due to inflammation, capillary congestion
eschar
Thick crust often related to necrosis, trauma, or thermal/chemical burn
excoriation
Erosions and/or ulcerations due to self-trauma
fissure
Excessive stratum corneum, confirmed via histopathology. This term is often used to describe the nasal planum and footpads.
fistula
Ulcer on skin surface that originates from and is contiguous with tracts extending into deeper, typically subcutaneous tissues
follicular casts
Accumulation of scale adherent to hair shaft
hyperkeratosis
Excessive stratum corneum, confirmed via histopathology. This term is often used to describe the nasal planum and footpads.
hyperpigmentation
Increased melanin in skin, often secondary to inflammation
hypopigmentation
Partial pigment loss
hypotrichosis
Lack of hair due to genetic factors or defects in embryogenesis.
leukoderma
Lack of cutaneous pigment
leukotrichia
Loss of hair pigment
lichenification
Thickening of the epidermis, often due to chronic inflammation resulting in exaggerated texture
macule
Flat lesion associated with color change <1cm
melanosis
Increased melanin in skin, may be secondary to inflammation.
miliary
Multifocal, papular, crusting dermatitis; a descriptive term, not a diagnosis
morbiliform
A erythematous, macular, papular rash; the erythematous macules are typically 2-10 mm in diameter with coalescence to form larger lesions in some areas
nodule
A solid elevation >1cm
onychodystrophy
Abnormal nail morphology due to nail bed infection, inflammation, or trauma; may include: Onychogryphosis, Onychomadesis, Onychorrhexis, Onychoschizia
onychogryphosis
Abnormal claw curvature; secondary to nail bed inflammation or trauma
onychomadesis
Claw sloughing due to nail bed inflammation or trauma
onychorrhexis
Claw fragmentation due to nail bed inflammation or trauma
onychoschizia
Claw splitting due to nail bed inflammation or trauma
papule
Solid elevation in skin ≤1cm
papules
Solid elevation in skin ≤1cm
paronychia
Inflammation of the nail fold
patch
Flat lesion associated with color change >1cm
petechiae
Small erythematous or violaceous lesions due to dermal bleeding
phlebectasia
Venous dilation; most commonly associated with hypercortisolism
plaques
Flat-topped elevation >1cm formed of coalescing papules or dermal infiltration
pustule
Raised epidermal infiltration of pus
reticulated
Net-like arrangement of lesions
scale
Accumulation of loose fragments of stratum corneum
scar
Fibrous tissue replacing damaged cutaneous and/or subcutaneous tissues
serpiginous
Undulating, serpentine (snake-like) arrangement of lesions
telangiectasia
Permanent enlargement of vessels resulting in a red or violet lesion (rare)
ulcer
A defect in epidermis that penetrates the basement membrane. Histopathology may be needed to differentiate from an erosion.
urticaria
Wheals (steep-walled, circumscribed elevation in the skin due to edema ) due to hypersensitivity reaction
vesicle
Fluid-filled elevation of epidermis, <1cm
wheal
Steep-walled, circumscribed elevation in the skin due to edema