Differential Diagnosis for 56 YOF with Localized Swelling 24 hrs post Bee Sting

• Single most likely diagnosis:
  • Localized allergic reaction: This is the most common reaction to a bee sting, characterized by redness, swelling, and pain at the site of the sting. The timing of 24 hours post-sting is consistent with this diagnosis.
• Other Likely diagnoses:
  • Cellulitis: A bacterial infection of the skin that can occur after a bee sting, especially if the sting site becomes contaminated. Symptoms include redness, swelling, warmth, and pain.
  • Insect bite reaction: Similar to a localized allergic reaction but can be caused by other insects. The reaction can vary in severity and presentation.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Anaphylaxis (late presentation): Although anaphylaxis typically presents immediately after the sting, some cases can have a delayed onset. It's crucial to monitor for symptoms such as difficulty breathing, rapid heartbeat, and a fall in blood pressure.
  • Necrotizing fasciitis: A rare but severe infection that can occur after a bee sting, characterized by severe pain, swelling, and necrosis of the skin and underlying tissues.
• Rare diagnoses:
  • Serum sickness: A rare immune system reaction to certain medications or antiserums, which can also occur after a bee sting. Symptoms include fever, rash, and joint pain, typically appearing 7-14 days after the sting.
  • Arthropod-borne infections: In rare cases, bee stings can transmit diseases like tularemia or leptospirosis, depending on the region and the bee's exposure to infected animals.