Differential Diagnosis for Fever with Rash
- Single most likely diagnosis
- Viral exanthem (e.g., roseola, measles, chickenpox): This is often the most common cause of fever with rash in children and adults, characterized by a widespread rash and fever, with the specific virus determining the appearance and distribution of the rash.
- Other Likely diagnoses
- Bacterial infections (e.g., streptococcal pharyngitis, staphylococcal skin infections): These can cause fever and rash, often with additional symptoms like sore throat or localized skin lesions.
- Allergic reactions (e.g., urticaria, drug rash): These can present with fever and rash, especially if the reaction is severe or involves a medication.
- Insect-borne illnesses (e.g., Lyme disease, Rocky Mountain spotted fever): Depending on the geographic location and exposure history, these diseases can cause fever and rash.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningococcemia: A severe, life-threatening infection that can cause fever, rash, and rapidly progressing illness, requiring immediate medical attention.
- Toxic shock syndrome: A condition caused by bacterial toxins, leading to fever, rash, and severe systemic symptoms, which is fatal if not promptly treated.
- Rocky Mountain spotted fever: While listed under other likely diagnoses, it's crucial to not miss this due to its high mortality rate if not treated early.
- Rare diagnoses
- Kawasaki disease: An acute febrile illness of childhood characterized by fever, rash, and other specific criteria, which can lead to cardiac complications if not recognized and treated.
- Erythema multiforme: A skin condition characterized by target lesions, often triggered by infections or medications, which can be severe and requires specific management.
- Stevens-Johnson syndrome: A severe skin and mucous membrane disorder, usually a reaction to medication or infection, which can be life-threatening and requires immediate medical intervention.