Small Animal Dermatology, 3rd edition

550 DISEASES/DISORDERS

Standard ointments and lotions may be occlusive and perpetuate disease unless

used judiciously

NAC: 2% solution used to disrupt biofilm formation to increase antibiotic effi-

cacy; administered systemically to reduce chemotherapy-induced ototoxicity

Antiparasite: ivermectin, amitraz, pyrethrins, milbemycin, and thiabendazole.

 Systemic medication:
May be required if topical therapy is ineffective or cannot be administered due

to patient temperament or pain

Cytological examination of exudates helps determine the type of systemic med-

ication needed

Inflammation perpetuates disease; high-dose corticosteroids may be required

initially to reduce swelling of the canal epithelium so that medications can be

instilled effectively

Otitis interna, otitis media, and chronic/severe otitis externa may require sys-

temic medication for at least 4–6 weeks

Antibiotic choice should be based on culture/sensitivity with recurrent infec-

tions; should be performed when initial treatment is ineffective

Staphylococcal bacteria: cephalexin 22 mg/kg PO BID, amoxicillin trihydrate-

clavulanate potassium 10–15 mg/kg PO BID; clindamycin 11 mg/kg PO q24h

to BID for bone involvement; mupirocin topical solution, and chloramphenicol

40 mg/kg PO BID to TID – reserve unless indicated by culture and sensitivity

testing

Mixed or rod bacteria: fluoroquinolone: trimethoprim-sulfadiazine 10–15 mg/kg

PO BID, ormetoprim-sulfadimethoxine 55 mg/kg PO first day then 27.5 mg/kg

PO q24h, enrofloxacin 10–20 mg/kg PO q24h (dogs) maximum 5 mg/kg PO

q24h (cats) – dose may be divided and administered BID, ciprofloxacin 20–

25 mg/kg PO q24h, orbifloxacin 2.5–7.5 mg/kg PO q24h, marbofloxacin 2.75–

5.5 mg/kg PO q24h – higher-range dosage recommended forPseudomonasspp.

infection

Subcutaneously: amikacin 20 mg/kg by subcutaneous injection q24h; beta-

lactam: ticarcillin disodium/clavulanate potassium 10–25 mg/kg by intramus-

cular injection, imipenem 5 mg/kg by subcutaneous or intramuscular injection

TID to QID, meropenem 8.5 mg/kg BID (dogs), 10 mg/kg BID (cats), ceftazidime

30 mg/kg by subcutaneous injection TID to QID

Antifungal: may be prescribed along with topical therapy for otitis media; keto-

conazole 5 mg/kg PO q24h to BID, fluconazole 5 mg/kg PO q24h to BID, itra-

conazole 5 mg/kg PO q24h; usefulness of oral antifungal medications in otitis

externa is controversial

Antiinflammatory: prednisolone 1–2 mg/kg PO q24h, dexamethasone 0.1–

0.2 mg/kg PO q24h, triamcinolone 0.1–0.2 mg/kg PO q24h – tapering dosages;

intralesional triamcinolone (0.1 mg/kg total dosage placed in multiple sites)

Parasiticide: ivermectin 200–400μg/kg by subcutaneous injection every 2 weeks

for three treatments or PO weekly for four treatments, selamectin – as labeled,

moxidectin – as labeled, isoxazolines (afoxolaner, fluralaner, sarolaner) – as

labeled.