Which disease is characterized by a "bull’s-eye" rash?

Lyme disease is characterized by a distinctive "bull's-eye" rash, also known as erythema migrans. This rash typically exhibits a central red spot surrounded by a clear area and a red halo, which resembles a target or bull's-eye. The appearance of this rash usually occurs at the site of a tick bite and is a key clinical feature of Lyme disease, especially in its early stage. Prompt recognition of this rash is crucial for diagnosis and treatment, as early intervention with appropriate antibiotics can effectively resolve the infection and prevent complications.

Other conditions mentioned do not present with this specific type of rash. Rocky Mountain spotted fever, for instance, has a different rash presentation characterized by petechiae and a maculopapular rash that often begins on the wrists and ankles. Measles has a characteristic rash that starts at the hairline and spreads downward, while scarlet fever is associated with a rash that feels like sandpaper and follows a strep throat infection. Thus, the presence of a "bull's-eye" rash is a strong indicator of Lyme disease.