Differential Diagnosis for Hives and Nausea, Vomiting in a 15-Month-Old
Single Most Likely Diagnosis
- Allergic Reaction: This is the most likely diagnosis given the symptoms of hives and gastrointestinal upset, which are common manifestations of an allergic reaction in children. The reaction could be due to a food allergy, an insect bite, or exposure to another allergen.
Other Likely Diagnoses
- Viral Exanthem: Many viral infections can cause rashes and gastrointestinal symptoms in children. The presence of hives could be part of a viral exanthem, which is a rash caused by a viral infection.
- Food Allergy: A specific type of allergic reaction, food allergies can cause hives, nausea, vomiting, and other symptoms after the ingestion of a particular food item.
- Insect Bite or Sting: Insect bites or stings can cause localized or generalized reactions, including hives and systemic symptoms like nausea and vomiting.
Do Not Miss Diagnoses
- Anaphylaxis: Although it might seem like an extreme version of an allergic reaction, anaphylaxis is a life-threatening condition that requires immediate recognition and treatment. Symptoms can include hives, swelling, nausea, vomiting, and difficulty breathing.
- Meningitis: While less common, meningitis can present with rash (though typically not hives) and systemic symptoms like nausea and vomiting. It's crucial to consider this diagnosis, especially if there are signs of severe illness or neurological symptoms.
- Septic Shock: In rare cases, a severe infection can lead to septic shock, which might initially present with non-specific symptoms like nausea, vomiting, and rash.
Rare Diagnoses
- Urticaria due to Autoimmune Disorders: Certain autoimmune conditions, like autoimmune urticaria, can cause chronic hives. While rare in this age group, it's a consideration if the symptoms persist or recur without an identifiable cause.
- Mastocytosis: A rare condition characterized by the accumulation of mast cells in the skin or other organs, mastocytosis can cause hives, nausea, vomiting, and other symptoms due to the release of histamine and other mediators.
- Erythema Multiforme: A skin condition characterized by target lesions, erythema multiforme can sometimes present with hives-like symptoms and is often associated with viral infections or other triggers.