Differential Diagnosis for Rash
- Single most likely diagnosis
- Drug-induced petechiae or purpura: The recent introduction of losartan-hydrochlorothiazide 2 months ago could be the culprit, as some medications are known to cause petechiae or purpura-like rashes. The fact that the rash spares the groin and is not accompanied by systemic symptoms or fever makes this a plausible option.
- Other Likely diagnoses
- Vasculitis: Given the description of slightly raised lesions, vasculitis could be a consideration, although the lack of systemic symptoms and fever makes it less likely.
- Thrombocytopenia: Although not directly mentioned, the use of testosterone supplements could potentially affect platelet count, leading to thrombocytopenia, which might manifest as petechiae.
- Allergic reaction: An allergic reaction to the testosterone supplement or another environmental factor could also present with a petechial rash.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningococcemia: Although the patient does not have fever or systemic symptoms, meningococcemia can present with a petechial rash and is a medical emergency. The recent travel to Ireland could be a risk factor, as certain regions have higher incidence rates.
- Disseminated intravascular coagulation (DIC): This condition can cause petechiae and would be critical to identify due to its high mortality rate if left untreated.
- Thrombotic thrombocytopenic purpura (TTP): Another condition that, although rare, could present with petechiae and would require immediate medical attention.
- Rare diagnoses
- Henoch-Schönlein purpura (HSP): A form of vasculitis that can present with purpura, although it typically affects the lower extremities and buttocks, and is often accompanied by abdominal pain and arthritis.
- Ehlers-Danlos syndrome: A genetic disorder that can affect skin and blood vessels, potentially leading to easy bruising and petechiae, but this would likely be a long-standing condition rather than an acute presentation.