Differential Diagnosis for Target-like Rash
- Single most likely diagnosis
- Erythema Multiforme (EM): This condition is characterized by a target-like appearance of the rash, often triggered by infections (especially herpes simplex) or medications. It's a common cause of such a rash and should be considered first due to its classic presentation.
- Other Likely diagnoses
- Lupus Erythematosus: Systemic lupus erythematosus (SLE) can present with a variety of skin manifestations, including a target-like rash, though it's more commonly associated with a malar rash. The presence of other systemic symptoms would support this diagnosis.
- Dermatomyositis: This is an inflammatory disease characterized by skin rash and muscle weakness. The rash can sometimes appear target-like, especially on the hands.
- Fixed Drug Eruption: This condition causes a rash that can appear target-like and is usually triggered by medications. Lesions typically recur at the same site each time the offending drug is taken.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN): These are severe skin conditions usually triggered by medications. They can start with a target-like rash but quickly progress to widespread skin necrosis and detachment, which can be life-threatening. Early recognition and withdrawal of the offending drug are crucial.
- Rocky Mountain Spotted Fever (RMSF): This tick-borne illness can present with a rash that may initially appear target-like, though it more commonly progresses to a petechial rash. It's critical to consider RMSF due to its high mortality if not treated promptly with antibiotics.
- Rare diagnoses
- Sweet Syndrome: Also known as acute febrile neutrophilic dermatosis, it presents with fever, leukocytosis, and tender, erythematous skin lesions that can occasionally appear target-like. It's often associated with underlying infections, inflammatory bowel disease, or malignancies.
- Rowell Syndrome: A rare condition characterized by a lupus-like syndrome with a distinctive target-like rash, often associated with lupus erythematosus or other autoimmune conditions. It's very rare and usually considered when other diagnoses have been ruled out.