Differential Diagnosis for a 6-year-old with a Rash after Tick Removal
- Single most likely diagnosis
- Lyme disease: Given the history of tick removal and the subsequent appearance of a rash, Lyme disease is a strong consideration, especially with a family history of the disease. The rash, likely erythema migrans, is a common initial presentation of Lyme disease.
- Other Likely diagnoses
- Southern tick-associated rash illness (STARI): This condition presents with a similar rash to erythema migrans but is associated with the bite of the lone star tick. It's less common than Lyme but should be considered, especially if the tick was identified as a lone star tick.
- Tick bite granuloma: This is a localized reaction to a tick bite that can cause a rash or nodule at the bite site. It's less specific than erythema migrans but can occur after a tick bite.
- 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 severe and potentially life-threatening disease transmitted by ticks. Early recognition and treatment are crucial, making it a "do not miss" diagnosis.
- Tularemia: This bacterial infection can be transmitted by tick bites and has a wide range of clinical presentations, from skin ulcers to severe systemic illness. Its potential severity warrants consideration in the differential diagnosis.
- Rare diagnoses
- Babesiosis: A parasitic disease transmitted by ticks, babesiosis can cause a range of symptoms from mild to severe. It's more common in certain geographic areas and in individuals with splenectomy or immunocompromised states.
- Ehrlichiosis/Anaplasmosis: These are bacterial infections transmitted by ticks that can cause fever, headache, and fatigue, among other symptoms. They are less common than Lyme disease but should be considered in patients with exposure to ticks and compatible symptoms.