Differential Diagnosis for Petechiae, Facial Itchy Rash
- Single Most Likely Diagnosis
- Atopic Dermatitis (Eczema): This condition is characterized by itchy, inflamed skin and can sometimes present with petechiae due to scratching. The facial involvement and itchiness are common in atopic dermatitis.
- Other Likely Diagnoses
- Contact Dermatitis: An allergic or irritant reaction to substances like cosmetics, soaps, or metals can cause an itchy rash on the face, potentially accompanied by petechiae if the skin is scratched.
- Urticaria: Hives can appear anywhere on the body, including the face, and are often itchy. While petechiae are not a primary feature, severe scratching can lead to their appearance.
- Insect Bites: Certain insect bites can cause itchy rashes and, in some cases, petechiae, especially if there's an allergic reaction or if the bites become infected.
- Do Not Miss Diagnoses
- Meningococcemia: This is a life-threatening infection that can cause a rash, which may initially appear as petechiae. Although it's less common, the severity of the condition necessitates its consideration, especially if accompanied by symptoms like fever, headache, or stiff neck.
- Thrombocytopenia: Low platelet count can lead to petechiae. If the patient also has an itchy rash, it could be due to a separate condition or a manifestation of the underlying cause of thrombocytopenia, such as an autoimmune disorder.
- Vasculitis: Certain types of vasculitis, like leukocytoclastic vasculitis, can present with a rash and petechiae. The condition can be serious and requires prompt diagnosis and treatment.
- Rare Diagnoses
- Erythema Multiforme: A skin condition characterized by target lesions, which can sometimes appear on the face and may be accompanied by petechiae in severe cases.
- Sweet Syndrome: Also known as acute febrile neutrophilic dermatosis, it can cause a rash and may include petechiae, though it's more commonly associated with fever and neutrophilia.
- Amyloidosis: In rare cases, amyloidosis can cause skin lesions, including petechiae, though this would typically be part of a broader systemic disease presentation.