Differential Diagnosis for 58-year-old Female with 3-day History of Hives
Single Most Likely Diagnosis
- Allergic reaction to amoxicillin: The patient is on amoxicillin for a sore throat, and the onset of hives is a common presentation of an allergic reaction to medications, especially antibiotics like amoxicillin.
Other Likely Diagnoses
- Viral exanthem: Many viral infections can cause hives, and the patient's recent sore throat could be a viral upper respiratory infection.
- Urticaria due to other medications: Although amoxicillin is the most obvious culprit, other medications the patient may be taking could also cause hives.
- Autoimmune disorders: Conditions like thyroiditis or lupus can cause urticaria, although these would be less common and might be accompanied by other symptoms.
Do Not Miss Diagnoses
- Anaphylaxis: Although the patient only reports hives, anaphylaxis is a life-threatening condition that can present with urticaria and progress to more severe symptoms like angioedema, respiratory distress, and cardiovascular collapse. It's crucial to assess for other signs of anaphylaxis.
- Stevens-Johnson syndrome (SJS) or Toxic Epidermal Necrolysis (TEN): These are severe skin and mucous membrane disorders usually caused by medications. While rare, they are potentially fatal and require immediate recognition and treatment.
- Mastocytosis: A condition where there's an accumulation of mast cells in the skin, which can cause urticaria and anaphylaxis. It's less common but important to consider, especially if the patient has a history of recurrent or severe episodes.
Rare Diagnoses
- Urticarial vasculitis: An inflammation of the blood vessels that can cause hives, but it's a rare condition and usually accompanied by other symptoms like purpura or systemic symptoms.
- Parasitic infections: Certain parasites can cause urticaria, but this would be uncommon in the context provided and might be associated with travel history or specific exposures.
- Malignancy-associated urticaria: Some cancers can cause urticaria, but this is rare and would likely be accompanied by other symptoms or signs of malignancy.