Differential Diagnosis for Sore Throat and Lip Swelling

The patient presents with symptoms of sore throat and lip swelling, with a history of allergy to fish and recent exposure to a fishing environment through her new home. Considering these factors, the differential diagnoses can be categorized as follows:

• Single Most Likely Diagnosis

  • Allergic Reaction: Given the patient's known allergy to fish and the recent exposure to a fish-contaminated environment (the new house), an allergic reaction is the most plausible explanation. The symptoms of sore throat and lip swelling are consistent with an allergic response, which could range from mild to severe (anaphylaxis).

• Other Likely Diagnoses

  • Irritant Contact Dermatitis or Allergic Contact Dermatitis: Exposure to substances in the new house, potentially used for fishing or fish cleaning, could cause skin and mucous membrane irritation or an allergic contact dermatitis, leading to lip swelling and possibly affecting the throat if inhaled or if there's hand-to-mouth transmission.
  • Infection (Viral or Bacterial): Although less directly related to the provided history, infections such as viral pharyngitis or bacterial tonsillitis could cause sore throat. Lip swelling could be secondary to an infection or a separate condition.

• Do Not Miss Diagnoses

  • Anaphylaxis: Although mentioned under allergic reaction, anaphylaxis is a life-threatening condition that requires immediate recognition and treatment. Symptoms can include severe swelling, difficulty breathing, and a drop in blood pressure, among others.
  • Angioedema: This condition involves deep tissue swelling and can be life-threatening if it affects the airway. It can be allergic or non-allergic in nature and is crucial to identify promptly.

• Rare Diagnoses

  • Paralytic Shellfish Poisoning or Ciguatera Fish Poisoning: If the patient was exposed to contaminated fish or shellfish through the house (less likely but possible through contaminated utensils, surfaces, etc.), these poisonings could potentially cause a range of symptoms, including neurological and gastrointestinal issues, though they are less directly linked to the symptoms described.
  • Other Environmental Allergens or Toxins: The new house could potentially expose the patient to other allergens or toxins (e.g., mold, pesticides) that might cause or contribute to her symptoms, though these would be less directly related to fish or fishing activities.