Differential Diagnosis for Rash with Central Clearing that is Widespread
- Single most likely diagnosis
- Erythema migrans (Lyme disease): This is the most likely diagnosis due to the characteristic rash with central clearing, which is often seen in the early stages of Lyme disease. The rash can be widespread and is usually accompanied by other symptoms such as fever, headache, and fatigue.
- Other Likely diagnoses
- Tinea corporis (ringworm): This fungal infection can cause a rash with central clearing, although it is typically more localized than widespread. It can spread to other parts of the body through skin-to-skin contact or by sharing personal items.
- Nummular dermatitis: This condition is characterized by coin-shaped patches of dry, itchy skin that can have central clearing. While it's not typically widespread, it can occur in multiple areas of the body.
- Psoriasis: Although psoriasis typically presents with well-defined, scaly plaques, some forms like guttate psoriasis can have a more widespread distribution with lesions that may have central clearing.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Rocky Mountain spotted fever (RMSF): This tick-borne illness can cause a rash that may have central clearing, although it's more commonly associated with a petechial rash. RMSF is a serious condition that requires prompt treatment to prevent severe complications or death.
- Southern tick-associated rash illness (STARI): Also known as Masters disease, this condition is caused by the bite of the lone star tick and can cause a rash similar to erythema migrans. While it's typically not serious, it can be mistaken for Lyme disease, and the differential diagnosis is crucial.
- Rare diagnoses
- Secondary syphilis: This stage of syphilis can cause a wide range of skin manifestations, including a rash with central clearing. However, this is less common and usually accompanied by other systemic symptoms.
- Pityriasis rosea: This condition causes a rash that can have central clearing, but it typically starts with a herald patch followed by a wider distribution of smaller lesions, often in a Christmas tree pattern on the back.