Differential Diagnosis for Dog Bite with Swollen Pinky Finger

Single most likely diagnosis

• Cellulitis: This is the most likely diagnosis given the symptoms of swelling, redness, and numbness in the pinky finger after a dog bite. Cellulitis is a common bacterial skin infection that can occur after an animal bite, and the presentation matches the symptoms described.

Other Likely diagnoses

• Abscess: An abscess is a possible diagnosis, especially if the infection has localized and formed a pocket of pus. The symptoms of swelling, redness, and numbness could be indicative of an abscess, particularly if there is a history of inadequate wound care or delayed treatment.
• Tenosynovitis: This is an infection of the tendon sheath, which could occur after a dog bite, especially if the bite penetrated deeply and involved the tendons. Symptoms such as numbness and swelling could be consistent with tenosynovitis, particularly if there is limited mobility of the finger.
• Osteomyelitis: Although less common, osteomyelitis (an infection of the bone) could be a consideration, especially if the dog bite was deep and penetrated to the bone. However, this would typically present with more systemic symptoms such as fever and might take longer to develop.

Do Not Miss diagnoses

• Rabies: Although rare in many parts of the world, rabies is a potentially deadly diagnosis that must be considered in any animal bite, including dog bites. The incubation period can vary, and early symptoms can be non-specific, making it crucial not to miss this diagnosis.
• Tetanus: Another critical infection to consider is tetanus, which can occur after any wound, including animal bites. Tetanus infection can lead to severe muscle stiffness and spasms and is preventable with proper wound care and vaccination.
• Sepsis: Sepsis, a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs, is a potential complication of any infection, including those resulting from dog bites. Early recognition and treatment are critical.

Rare diagnoses

• Eikenella corrodens Infection: This is a rare bacterium that can be found in the mouths of dogs and cats and can cause infections in humans after bites. It might present similarly to other bacterial infections but can be resistant to some antibiotics.
• Capnocytophaga canimorsus Infection: This bacterium is also found in the mouths of dogs and can cause severe infections in humans, particularly those who are immunocompromised. It is rare but can lead to significant morbidity and mortality if not recognized and treated promptly.
• Pasteurella multocida Infection: While not the most common cause of infection after a dog bite, Pasteurella multocida is a bacterium that can be transmitted through bites and can cause a variety of infections, including cellulitis and abscesses.