Antimicrobials for skin disease Flashcards
What are the general principles of antimicrobial therapy in dermatological cases?
Ensure bacteria are involved using cytology
Use topical antimicrobials where possible - minimise use of systemic antibiotics
Use the narrowest spectrum and lowest EMA category antibiotic that will be effective
correct underlying cause
What are the first steps in managing bite and traumatic wounds in small animals?
Decontaminate & debride (lavage ± surgical debridement ± dressings)
When should further investigation or surgical exploration be considered for bites and traumatic wounds in small animals?
If wound is located over abdomen or thorax, imaging &/or surgical exploration may be required
When are systemic antibiotics indicated in small animals with bites or traumatic wounds?
If animal is systemically unwell, pyrexic, or if cavity penetration is suspected
Recommended antibiotics:
Cefuroxime ± cefalexin.
Amoxicillin/clavulanate
How is surface pyoderma treated in small animals
Topical treatment
- 2-4% chlorhexidine or other antiseptic
If not responsive or very severe:
- Fusidic acid +- glucocorticoid (cocci)
- Silver sulphadiazine (rods)
What is the preferred first-line treatment for superficial pyoderma in small animals?
Topical treatment
2–4% chlorhexidine q1–3 days
Review after 2–3 weeks & continue until underlying cause is controlled
When should systemic antibiotics be used for superficial pyoderma in small animals?
If topical therapy fails or infection is severe
Always use systemic antibiotics in combination with topical antiseptics
Treat for 2 weeks, then reassess
Investigate resistance if poor response (via cytology, culture & susceptibility testing)
What systemic antibiotics can be used for superficial pyoderma if topical treatment fails?
Clindamycin (first choice due to narrowest spectrum)
Trimethoprim/sulphonamide
Cefalexin
Amoxicillin/clavulanate
When should culture and sensitivity testing (C&S) be performed in small animals with superficial pyoderma?
If there is a history of MRSP/MRSA (methicillin resistant staphylococcus bacteria)
If patient has had prior antibiotic courses
If rods are seen on cytology
When should systemic antibiotics be started for deep pyoderma in small animals?
ONLY if infection is painful OR if there is risk of septicaemia
Always perform culture & susceptibility testing before starting systemic antibiotics
What is the recommended topical treatment for deep pyoderma in small animals?
Concurrent topical treatment with 2–4% chlorhexidine q1–3 days
Topical therapy should always be used alongside systemic antibiotics when indicated
What is the primary approach to treating otitis externa in small animals?
Topical treatment ONLY
Assess tympanic membrane integrity – avoid ototoxic products if ruptured
How is cocci-associated otitis externa treated in small animals?
First-line treatment → Antiseptic ear cleaner + topical steroids
If no response after 7 days, ADD topical antibiotics:
Fusidic acid/framycin.
Florfenicol
How is rod-shaped bacteria-associated otitis externa treated in small animals?
First-line treatment → Antiseptic ear cleaner while awaiting culture results
If culture confirms rods, ADD:
Gentamicin.
Framycetin
What additional steps are needed for Pseudomonas-associated otitis externa in small animals?
ADD TrisEDTA + topical antibiotics to treatment
Continue treatment until cytology is negative & underlying cause is corrected
How are superficial bacterial skin infections treated in horses?
Topical antibacterial (e.g. chlorhexidine, silver sulphadiazine) if possible
Correct underlying cause
How are deep pyodermas/cellulitis treated in horses?
Systemic antibiotics
Ideally base on bacterial C&S testing
TMPS (sulfadiazine + trimethoprim) where possible – only licensed oral antibiotic available
How should small, superficial bacterial skin infections be treated in farm animals?
Use topical anti-bacterials/antiseptics
E.g.: Chlorhexidine-based products, tetracycline/thiamphenicol spray
Address underlying cause
How should large or more severe bacterial skin infections be treated in farm animals?
Use non-critically important systemic antibiotics:
- Penicillin
- Cephalosporins
- Oxytetracycline
Treat for 5 days, then reevaluate
Address Underlying Cause
What is the treatment of abscesses in all species except rabbits?
allow to mature and ‘point’ - poulticing/hot compresses may accelerate
Once mature => lance, drain and flush (NSAIDs if needed)
Appropriate antibiotics if systemically unwell, pyrexic or cellulitis present
How are abscesses treated in rabbits?
Caseous pus - cannot lance and drain
Culture and susceptibility testing (C&S) on section of abscess wall
Investigate cause e.g., dental disease
Antibiotics used in conjunction with surgical management (will not be curative alone)
Describe the treatment of dermatophytosis
Identify the fungus and any predisposing conditions
Remove infective fungal spores from coat (topical antifungal rinse/shampoo +/- clip hair) => reduce environmental contamination
+/- Systemic therapy
Clean environment as far as possible
Monitor response to therapy
Give examples of topics antifungal rinses/shampoos
Miconazole
- licensed as adjunctive treatment for dermatophytosis in cats (in combo with chlorhexidine)
- licensed for dogs for bacterial pyoderma
Enilconazole (imaverol) rinse
- cattle, horses, dogs
Human fungal creams, e.g., clotrimazole, can be used for local adjunctive treatment where wash inappropriate )e.g., near eyes)
Give examples of systemic antifungals
Itraconazole
- licensed for cats
Ketoconazole
- licensed for dogs, never cats
