Differential Diagnosis
- Single most likely diagnosis
- Lyme disease: Given the patient's symptoms of fever, fatigue, headache, and a rash following a tick bite, Lyme disease is the most likely diagnosis. The rash is often a distinctive "bull's-eye" rash, but it can also be atypical.
- Other Likely diagnoses
- Southern tick-associated rash illness (STARI): This condition also presents with a rash after a tick bite, but it is typically smaller and more circular than the Lyme disease rash. Symptoms can include fever, fatigue, and headache.
- Ehrlichiosis: This bacterial infection is transmitted by ticks and can cause fever, fatigue, headache, and rash. It is often accompanied by other symptoms such as muscle aches and joint pain.
- Anaplasmosis: Similar to Ehrlichiosis, Anaplasmosis is a tick-borne bacterial infection that can cause fever, fatigue, headache, and rash, along with other symptoms like muscle aches and joint pain.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Rocky Mountain spotted fever (RMSF): Although less common, RMSF is a serious and potentially life-threatening tick-borne illness that can present with fever, headache, and rash. It requires prompt treatment.
- Tick-borne relapsing fever (TBRF): This condition is caused by a different type of bacteria and can lead to recurring episodes of fever, headache, and other symptoms. It is less common but can be severe if not treated.
- Rare diagnoses
- Babesiosis: A parasitic infection transmitted by ticks, Babesiosis can cause fever, fatigue, and other symptoms, but it is relatively rare and often affects individuals with weakened immune systems.
- Tularemia: Also known as rabbit fever, Tularemia is a bacterial infection that can be transmitted by ticks and can cause a range of symptoms including fever, rash, and swollen lymph nodes. It is rare but can be serious if not treated promptly.