Differential Diagnosis for Swollen and Red Leg or Hand after Dog Bite

• Single most likely diagnosis:
  • Cellulitis: This is the most likely diagnosis given the symptoms of a swollen and red leg or hand after a dog bite. Cellulitis is a common bacterial skin infection that can occur after an animal bite, especially if the wound is not properly cleaned and cared for. The bacteria from the dog's mouth can enter the wound and cause infection, leading to redness, swelling, and warmth of the affected area.
• Other Likely diagnoses:
  • Abscess: An abscess is a collection of pus that can form in response to a bacterial infection. After a dog bite, an abscess can form if the bacteria from the dog's mouth enter the wound and cause a localized infection.
  • Lymphangitis: This is an infection of the lymphatic vessels, which can occur after a dog bite. Lymphangitis can cause redness, swelling, and warmth of the affected area, as well as fever and chills.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Rabies: Although rare in developed countries, rabies is a potentially deadly viral infection that can be transmitted through the bite of an infected animal. It is essential to consider rabies in the differential diagnosis, especially if the dog's vaccination status is unknown.
  • Tetanus: Tetanus is a bacterial infection that can occur after a dog bite, especially if the wound is deep or contaminated with dirt or debris. Tetanus can cause muscle stiffness, spasms, and rigidity, and can be life-threatening if not treated promptly.
  • Capnocytophaga canimorsus infection: This is a rare but potentially life-threatening bacterial infection that can occur after a dog bite. Capnocytophaga canimorsus is a bacterium that is commonly found in the mouths of dogs and can cause sepsis, meningitis, and other serious infections.
• Rare diagnoses:
  • Erysipeloid: This is a rare bacterial infection that can occur after a dog bite, especially if the wound is contaminated with dirt or debris. Erysipeloid can cause redness, swelling, and warmth of the affected area, as well as fever and chills.
  • Pasteurella multocida infection: This is a rare bacterial infection that can occur after a dog bite. Pasteurella multocida is a bacterium that is commonly found in the mouths of dogs and can cause a range of infections, including cellulitis, abscesses, and sepsis.