Differential Diagnosis for Itchy Petechiae
- Single most likely diagnosis
- Urticarial vasculitis: This condition is characterized by inflammation of the blood vessels, leading to itchy petechiae. The symptoms can resemble those of urticaria but with a more severe and prolonged course.
- Other Likely diagnoses
- Insect bite reactions: Certain insect bites can cause itchy petechiae, especially if there is an allergic reaction to the bite.
- Meningococcemia (early stages): Although typically associated with a more severe and acute presentation, early stages of meningococcemia can present with itchy petechiae before progressing to more severe symptoms.
- Henoch-Schönlein purpura (HSP): This condition is a form of vasculitis that affects blood vessels and is characterized by the deposition of immune complexes containing IgA. It can present with itchy petechiae, among other symptoms.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Thrombotic thrombocytopenic purpura (TTP): A rare blood disorder characterized by the formation of blood clots in small blood vessels throughout the body. It can present with petechiae, among other symptoms, and is life-threatening if not promptly treated.
- Disseminated intravascular coagulation (DIC): A condition characterized by both widespread clotting and bleeding in the vascular system. It can present with petechiae and is often associated with severe underlying conditions.
- Malignancy (e.g., lymphoma or leukemia): Certain types of cancer can cause itchy petechiae due to bone marrow infiltration or paraneoplastic syndromes.
- Rare diagnoses
- Ehlers-Danlos syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. Some types can present with easy bruising and petechiae.
- Amyloidosis: A condition characterized by the deposition of amyloid (a particular type of protein) in various tissues of the body. It can cause petechiae, among a wide range of other symptoms, depending on the organs affected.
- Scurvy: A disease resulting from vitamin C deficiency, which can cause connective tissue weakness, leading to bleeding and petechiae.