Differential Diagnosis for Dog Scratch with Blister on Hand
- Single Most Likely Diagnosis
- Cat scratch disease (Bartonellosis): Although the question mentions a dog scratch, cat scratch disease is a common condition that can cause a blister or pustule at the site of the scratch, and it's possible the patient may have come into contact with a cat as well. The disease is caused by the bacterium Bartonella henselae, which is typically transmitted through scratches from infected cats.
- Other Likely Diagnoses
- Cellulitis: A common bacterial skin infection that can occur after a dog scratch, causing redness, swelling, and blistering.
- Pasteurella multocida infection: A bacterium commonly found in the mouths of dogs and cats, which can cause skin infections, including cellulitis and abscesses, after a bite or scratch.
- Erysipelas: A type of skin infection caused by group A Streptococcus, which can cause a blistering rash and is often associated with animal bites or scratches.
- Do Not Miss Diagnoses
- Rabies: Although rare, rabies is a deadly viral disease that can be transmitted through the saliva of infected animals, including dogs. It's essential to consider this diagnosis, especially if the dog's vaccination status is unknown.
- Tetanus: A bacterial infection caused by Clostridium tetani, which can enter the body through wounds, including scratches. Tetanus can cause severe muscle stiffness, spasms, and rigidity, and can be life-threatening if left untreated.
- Rare Diagnoses
- Capnocytophaga canimorsus infection: A rare but potentially life-threatening bacterial infection caused by a bacterium commonly found in the mouths of dogs. It can cause sepsis, meningitis, and other serious complications, especially in people with weakened immune systems.
- Mycobacterium marinum infection: A rare bacterial infection caused by a bacterium found in water and soil, which can enter the body through scratches or cuts. It can cause skin lesions, abscesses, and other symptoms.