Differential Diagnosis for Petechial Rash and Fever in an 8-year-old
Single Most Likely Diagnosis
- Idiopathic Thrombocytopenic Purpura (ITP): This condition is characterized by low platelet count, leading to petechiae, and is often preceded by a viral infection, which could explain the fever. It's a common cause of petechial rash in children.
Other Likely Diagnoses
- Viral Infections (e.g., Chickenpox, Measles): Certain viral infections can cause both fever and a rash that may include petechiae. The specific virus can often be identified based on the appearance of the rash and other symptoms.
- Infectious Mononucleosis: Caused by Epstein-Barr virus, this condition can lead to fever, sore throat, and sometimes a petechial rash, particularly on the palate.
- Allergic Reactions or Vasculitis: Conditions like Henoch-Schönlein purpura can cause a petechial or purpuric rash along with fever and other systemic symptoms.
Do Not Miss Diagnoses
- Meningococcemia: A life-threatening infection caused by Neisseria meningitidis, characterized by fever, petechial or purpuric rash, and can rapidly progress to sepsis or meningitis. Early recognition and treatment are crucial.
- Disseminated Intravascular Coagulation (DIC): A condition that can arise from severe infections, trauma, or other causes, leading to both clotting and bleeding, which may manifest as petechiae and fever.
- Leukemia: Although less common, acute leukemias can present with petechiae due to bone marrow failure, along with fever and other systemic symptoms.
Rare Diagnoses
- Thrombotic Thrombocytopenic Purpura (TTP): A rare disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia, and renal failure, which can present with fever and petechial rash.
- Hemolytic Uremic Syndrome (HUS): Typically follows a diarrheal illness caused by E. coli O157:H7, leading to renal failure, thrombocytopenia, and microangiopathic hemolytic anemia, which might include petechiae in its presentation.
- Autoimmune Disorders (e.g., Systemic Lupus Erythematosus): Can cause a wide range of symptoms including fever and petechial rash, though this would be uncommon in an 8-year-old without other systemic symptoms.