Family Nurse Practitioner Exam

What characteristic of erythema migrans is primarily noted in a patient after a tick bite?

1. The rash is typically painful and itchy

2. The rash has areas of central clearing

3. The rash appears as multiple small bumps

4. The rash is limited to only one area of the body

The correct answer is: The rash has areas of central clearing

Erythema migrans is a distinctive skin rash associated with Lyme disease, which is transmitted through tick bites. The prominent characteristic of this rash is the appearance of a red lesion often described as having areas of central clearing, creating a "bull's-eye" pattern. This occurs due to the expansion of inflammation as the infection progresses, with the center often fading as it resolves while the outer ring remains vibrant in color. The central clearing is indicative of the disease process, as the immune response develops and the inflammation moves radially outward from the site of the tick bite. This defining feature helps differentiate erythema migrans from other types of rashes that may appear after insect bites or allergic reactions, which do not exhibit the same morphology. Understanding the appearance of erythema migrans is critical for prompt diagnosis and treatment of Lyme disease, underscoring its relevance in clinical practice.