Differential Diagnosis for Dog Scratch
- Single most likely diagnosis:
- Cat-scratch disease (Bartonellosis): This is the most likely diagnosis because the bacteria Bartonella henselae is commonly transmitted through scratches from infected cats, and the presentation of a dog scratch could be a misidentification of the animal.
- Other Likely diagnoses:
- Cellulitis: A common infection of the skin and subcutaneous tissues that can occur after a dog scratch, especially if the scratch becomes contaminated with bacteria.
- Pasteurella multocida infection: This bacterium is commonly found in the mouths of dogs and can be transmitted through bites or scratches, leading to infections.
- Rabies (if the dog is not vaccinated): Although less common in areas with high vaccination rates, rabies is a significant concern if the dog's vaccination status is unknown.
- Do Not Miss diagnoses:
- Tetanus: Although rare, tetanus infection can occur through deep wounds, including scratches, if the tetanus vaccination is not up to date.
- Rabies (in areas with low vaccination rates or unknown vaccination status): Given the severity and lethality of rabies, it's crucial not to miss this diagnosis, especially in areas where dog vaccination rates are low.
- Capnocytophaga canimorsus infection: This bacterium is found in the mouths of dogs and can cause severe infections, particularly in individuals with compromised immune systems.
- Rare diagnoses:
- Erysipeloid: A rare infection caused by Erysipelothrix rhusiopathiae, which can be transmitted through contact with infected animals, including dogs.
- Leptospirosis: Although more commonly associated with water exposure, leptospirosis can be transmitted through contact with infected animal tissues, including a scratch from a dog that has the infection.
- Tularemia: A rare bacterial infection that can be transmitted through contact with infected animals, including dogs, although it's more commonly associated with rabbits and other small mammals.