Infectious Disease Compendium

Dog Bites

Diagnosis

"I done got bit by a dawg."

Sometimes you will see the odd infection, like a diabetic foot ulcer, that gets infected as the owner lets the dog lick the ulcer. Really. And ick. There was a case presented at conference years ago of a baby with Capnocytophagia meningitis. The family dog liked to lick the child's head, kind of like trying to get to the center of a tootsie roll pop for the animal.

And sometimes a dog will get a taste for sweet sweet human flesh (PubMed): "...a woman with numbness in her feet caused by diabetic neuropathy slept through a traumatic episode in which her Jack Russell terrier chewed off part of her slightly infected big toe...(PubMed)"

Epidemiologic Risks

Either being dumb enough to stick part of your anatomy near a dog or, more likely, another in an endless series of irresponsible dog owners who fail to understand the concept of a leash and let their vermin run free and bite someone.

And if dogs are fighting your arm or leg is not the best tool for breaking up the fight.

10-20% will go on to infection.

Microbiology

Streptococci, S. aureus, anaerobes, Pasteurella spp and Capnocytophagia canimorsus.

When tested by 16S ribosome methodology the wounds are filled with difficult to grow anaerobes, that, when grown, are ampicillin susceptible (Pubmed).

Staphylococcus pseudintermedius which can be mistaken as S.aureus (PubMed).

Bergeyella zoohelcum, found in the respiratory tract of dofs, leading to cellulitis and bacteremia (PubMed).

For unprovoked attacks, rabies needs to be considered.

Empiric Therapy

Washing the wound out is key; if the wound is not infected, amoxicillin/clavulanate po is reasonable prophylactic therapy, for the penicillin allergic patient, doxycycline OR a (quinolone PLUS metronidazole).

Follow closely and have a low threshold for iv therapy and debridement: third generation cephalosporins PLUS metronidazole, or quinolone PLUS metronidazole.

Specific Therapy

Debride, then prophylaxis is usually for 10 days.

Soft tissue infections (cellulitis or abscess) is iv until afebrile, then po for a total of 10-14 days.

Septic arthritis or tenosynovitis is 2 -3 weeks of iv.

Osteomyelitis is usually 6 weeks of iv.

Pearls

DO NOT USE first-generation cephalosporins, dicloxacillin, erythromycin.

In the asplenic, worry about sudden septic death from Capnocytophagia canimorsus.

Have a very low threshold for calling a surgeon, especially if the hand or face is involved.

"Primary suturing of wounds caused by dog bites resulted in similar infection rate compared to non-suturing. However, primary suturing exhibited improved cosmetic appearance (PubMed)."

The sooner the wound is tended to, the better the outcome.

Rants

A dogs mouth is not, contrary to popular myth, cleaner than a humans. The difference between a dog bit and a human bite is that the dog bite results in a rapid visit to the ER for care, the human bite is one drunk male punching another drunk male in the mouth, and then passing out in a corner for the rest of the night, with a subsequent delay in therapy and a worser presentation.

Please remember, dogs lick their ass. Bowel flora are therefore a consideration; that people let dogs lick their face is a conundrum I cannot solve.

To my knowledge no one ever developed superpowers have being bitten by a radioactive dog (PubMed). What would those powers be? The abilty to lick ones own butt? Bark all the time? Ruin peoples garden? No wonder there is no Marvel character of that sort.

Curious Cases

Relevant links to my Medscape blog

Dawg Bite

Can is not Ought

Dog Daze

Last Update: 06/23/18.