Ketoconazole Cephalexin for a Bacterial Infection of Dogs

Skin infections are common in dogs.

Skin infections are common in dogs, and can arise for a variety of reasons. Cephalexin and ketoconazole are a typical combination therapy for dogs with bacterial skin infections secondary to fungal infections. Both drugs work by interfering with the organisms' ability to form a cell wall, which leads to instability and death of the bacteria and fungus. Although a skin infection can take a long time to heal, oral medications supplemented by topical treatment generally provide the fastest treatment and the best outcome.

Bacterial Skin Infections

Constant licking provides a moist environment for bacteria to grow.

Bacterial skin infections can develop when a dog's skin is already inflamed or broken because of a wound, parasite infestation or a fungal infection. Frequently, the dog itself provides a perfect environment for bacteria to grow by repeatedly licking and chewing the affected area. The skin becomes warm from the inflammation and constantly moist from the licking, while chewing provides a break in the skin for bacteria to gain a foothold. Soon the inflammation is worse, the skin is itchier and discharge and crust develop as the bacteria multiply. Treatment involves an antibiotic to kill the bacteria as well as treatment for whatever caused the skin to become itchy and inflamed in the first place.

Cephalexin

Cephalexin is a broad-spectrum antibiotic that is similar to penicillin. Although approved by the U.S. Food and Drug Administration for use in humans only, veterinarians can legally prescribe cephalexin off-label for dogs and cats because of its effectiveness against bacterial infections. Cephalexin is given orally two or three times daily, and can cause some dogs to vomit if given on an empty stomach. To ensure complete eradication of the bacteria, the entire prescription should be finished even if the skin appears healed.

Ketoconazole

Ketoconazole is an antifungal medication that will treat the underlying infection that allowed the bacteria to take hold. It is given orally twice daily, and can cause vomiting or diarrhea, which should be reported to a veterinarian immediately. According to Dr. Mark Papich of Pet Place, ketoconazole can react unfavorably with certain medications, including antacids, anticonvulsants and some heart medications, and can cause cataracts in some dogs with prolonged use.

Additional Treatment

Topical antibiotic and antimicrobial medications can be applied two to three times daily to make the skin an inhospitable environment for fungus and bacteria. This allows the oral medications to eliminate the infection more efficiently. Pet MD also advocates periodic bathing with a benzoyl peroxide shampoo to help discourage the growth of infectious microorganisms.

Prognosis

The combination of antibiotics and antifungal medication will effectively eliminate both the primary fungal infection and the secondary bacterial infection, although several courses of treatment can be necessary. It is important to follow up with recheck appointments, allowing the veterinarian to monitor your dog's progress and alter the treatment plan if necessary.

References

• Pet MD: Bacterial Skin Infection in Dogs
• Pet Place: Ketoconazole (Nizoral)
• Pet Place: Cephalexin (Keflex)