Differential Diagnosis for Petechiae
The presence of petechiae, which are small, pinpoint spots on the skin that occur due to bleeding from small blood vessels, can be indicative of a variety of conditions. Here's a categorized differential diagnosis:
Single Most Likely Diagnosis
- Idiopathic Thrombocytopenic Purpura (ITP): This condition, characterized by low platelet count due to immune-mediated destruction, is a common cause of petechiae, especially in children and young adults. The low platelet count leads to an increased tendency to bleed, manifesting as petechiae.
Other Likely Diagnoses
- Viral Infections: Certain viral infections, such as influenza, mononucleosis, and HIV, can cause petechiae due to the body's immune response affecting platelet production or function.
- Medication Side Effects: Some medications, including antibiotics, antihistamines, and non-steroidal anti-inflammatory drugs (NSAIDs), can induce petechiae as a side effect, often by affecting platelet function or blood clotting.
- Trauma: Physical trauma, including minor injuries, can cause petechiae, especially in areas subjected to pressure or impact.
Do Not Miss Diagnoses
- Meningococcemia: This is a life-threatening infection caused by Neisseria meningitidis. Petechiae or purpura can be an early sign, and prompt recognition is crucial for timely antibiotic treatment.
- Disseminated Intravascular Coagulation (DIC): A condition characterized by both widespread clotting and bleeding in the vascular system, which can lead to petechiae among other symptoms. It is often associated with severe underlying conditions like sepsis or trauma.
- Leukemia: Certain types of leukemia, particularly acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), can present with petechiae due to bone marrow failure affecting blood cell production, including platelets.
Rare Diagnoses
- Henoch-Schönlein Purpura (HSP): A form of vasculitis that affects blood vessels and is characterized by the deposition of immune complexes containing IgA antibodies. It typically presents with purpura (which can include petechiae), abdominal pain, arthritis, and renal involvement.
- Thrombotic Thrombocytopenic Purpura (TTP): A rare disorder of the blood-coagulation system, causing extensive microscopic thrombi to form in the smallest blood vessels throughout the body. It is characterized by thrombocytopenia, microangiopathic hemolytic anemia, renal failure, neurological symptoms, and fever.
- Scurvy: Vitamin C deficiency can lead to impaired collagen synthesis, affecting blood vessel integrity and leading to petechiae, among other symptoms like malaise, inflammation of the gums, and joint pain.