Background and Aim: Pyoderma is common in dogs, and its treatment requires a novel medication rather than antibiotic therapy. This study aimed to determine the biochemical and histopathological changes associated with the topical application of Aloe vera 20% and 40% ointments, compared with gentamicin 0.1% ointment, in dogs suffering from Staphylococcus aureus pyoderma.

Materials and Methods: Serum and skin samples were collected from a negative control group before inducing pyoderma and from other subdivided groups on the 3rd, 7th, 10th, and 14th days post-inoculation for biochemical and histopathology examination.

Results: Serum aspartate aminotransferase, alanine aminotransferase (ALT), urea, and creatinine concentrations were higher in the positive control dogs on the 3rd day without treatment (DWT) compared with the negative control dogs (p<0.05). Compared with the healthy control dogs, serum zinc concentrations were lower in the positive control group on the 3rd, 7th, and 10th DWT and in dogs treated with A. vera 20% and gentamicin 0.1% ointments on the 3rd and 7th days post-treatment (p<0.05). Grossly, skin had erythema, pruritus, and pus-filled pustules of the untreated group. Microscopically, skin showed epidermal necrosis and edema, dermal collagen necrosis, and severe neutrophilic infiltration.

Conclusion: Compared with A. vera 20% and gentamicin 0.1% ointments, the topical application of A. vera 40% ointmentinduced quicker skin healing and decreased the inflammatory changes caused by S. aureus inoculation, based on biochemical and histopathological changes reflective of its curative efficiency. A. vera 40% ointment may be a suitable alternative to antibiotics for the treatment of staphylococcal pyoderma in dogs.

Keywords: Aloe vera biochemical and histopathology examination, gentamicin, pyoderma, Staphylococcus aureus.