Differential Diagnosis for Patient Exposed to Puppy with Worms

The patient's symptoms and exposure history suggest a parasitic infection. Here's a differential diagnosis organized into categories:

• Single Most Likely Diagnosis
  • Hookworm infection: The patient's exposure to a puppy producing worms from its rectum and the patient's symptom of anal itching are highly suggestive of hookworm infection. Hookworms can infect humans through contact with contaminated feces or soil, and anal itching is a common symptom.
• Other Likely Diagnoses
  • Roundworm (Toxocara) infection: While less likely than hookworm, roundworms can also infect humans through contact with contaminated feces or soil. However, the symptoms are often more systemic, such as fever, cough, and abdominal pain, rather than just anal itching.
  • Tapeworm infection: Although less common, tapeworms can infect humans through contact with contaminated feces or undercooked meat. The patient's symptoms could be consistent with a tapeworm infection, but it's less likely given the exposure history.
• Do Not Miss Diagnoses
  • Echinococcosis (Hydatid disease): This parasitic infection is caused by the Echinococcus tapeworm and can be life-threatening if left untreated. While rare, it's essential to consider this diagnosis, especially if the patient has a history of traveling to endemic areas or has been exposed to contaminated feces.
  • Strongyloidiasis: This parasitic infection can cause severe symptoms, including gastrointestinal distress, skin lesions, and respiratory problems. It's essential to consider this diagnosis, especially if the patient is immunocompromised or has a history of travel to endemic areas.
• Rare Diagnoses
  • Dipylidiasis (Flea tapeworm): This parasitic infection is caused by the Dipylidium caninum tapeworm and is typically transmitted through the ingestion of infected fleas. While rare, it's possible that the patient could have ingested an infected flea while sleeping with the puppy.
  • Trichuriasis (Whipworm): This parasitic infection is caused by the Trichuris trichiura whipworm and is typically transmitted through contaminated food or water. While rare, it's possible that the patient could have been exposed to contaminated feces or soil.