Differential Diagnosis
- Single most likely diagnosis
- Influenza: The patient's symptoms of flu-like illness, chills, sweats, and fatigue, along with a negative at-home COVID test, make influenza a likely diagnosis. The rash on one side of the scalp and face could be a secondary bacterial infection or a viral exanthem.
- Other Likely diagnoses
- Mononucleosis: The patient's prolonged fatigue, fever, and rash could be indicative of infectious mononucleosis, especially if the patient is young.
- Lyme disease: Although less common, the patient's rash on one side of the face and scalp could be a sign of Lyme disease, particularly if the patient has been exposed to ticks.
- Viral exanthem: The rash, along with the patient's flu-like symptoms, could be a viral exanthem caused by a variety of viruses, such as enterovirus or adenovirus.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningitis: The patient's symptoms of fever, chills, and rash, along with the location of the rash on the scalp and face, could be indicative of meningitis, particularly if the patient has a headache or stiff neck.
- Rocky Mountain spotted fever: The patient's rash, fever, and headache (if present) could be indicative of Rocky Mountain spotted fever, a tick-borne illness that can be deadly if not treated promptly.
- Ehrlichiosis/Anaplasmosis: These tick-borne illnesses can present with fever, chills, and rash, and can be severe if not treated promptly.
- Rare diagnoses
- Ramsay Hunt syndrome: The patient's rash on one side of the face and scalp could be a sign of Ramsay Hunt syndrome, a rare complication of varicella-zoster virus infection.
- Erythema migrans: Although the patient's rash is not typically described as a "bull's-eye" rash, it could still be a sign of erythema migrans, an early manifestation of Lyme disease.