# A 7-year-old child is brought to the emergency department with a 4-day history of fever, headache, and malaise. The parents report the child went camping in North Carolina 10 days ago. Which assessment finding would be most characteristic of Rocky Mountain spotted fever? > source: MyMerci (mymerci.kr) > url: https://mymerci.kr/pages/nclex_q.php?qn_id=542291 > language: ko > subject: Child Health ## 문제 A 7-year-old child is brought to the emergency department with a 4-day history of fever, headache, and malaise. The parents report the child went camping in North Carolina 10 days ago. Which assessment finding would be most characteristic of Rocky Mountain spotted fever? ## 보기 1. Koplik spots on the buccal mucosa 2. Vesicular rash starting on the trunk 3. Petechial rash beginning on wrists and ankles **✔ 정답** 4. Erythema migrans with central clearing **정답: 3** ## 해설 Rocky Mountain spotted fever is characterized by a petechial rash starting on wrists and ankles, which distinguishes it from other conditions. Koplik spots are seen in measles, vesicular rash in chickenpox, and erythema migrans in Lyme disease. ## 심화 해설 Clinical Reasoning and Differential Diagnosis The question presents a classic epidemiological and clinical scenario for Rocky Mountain spotted fever (RMSF). The child's history of camping in North Carolina, a known endemic area, combined with a prodrome of fever, headache, and malaise, should immediately raise suspicion for a tick-borne illness. The key to answering this question lies in recognizing the characteristic rash progression of RMSF and differentiating it from the rashes of other infectious diseases presented in the incorrect options. RMSF is a bacterial infection caused by Rickettsia rickettsii, transmitted by the bite of an infected tick. The pathophysiology involves the invasion of endothelial cells lining small blood vessels, leading to a generalized vasculitis. This vascular damage is responsible for the hallmark rash. The rash typically appears 2-5 days after the onset of fever. It begins as small, flat, pink, non-itchy macules on the wrists, ankles, and forearms, and then spreads centripetally to the trunk, palms, and soles. A critical and defining characteristic of the rash as the disease progresses is its evolution into a petechial form. The vasculitis causes leakage of blood from damaged vessels into the skin, initially presenting as blanching maculopapules that later become non-blanching petechiae or purpura. This finding of a petechial rash beginning on the wrists and ankles is a classic, high-yield sign for RMSF and represents a medical emergency. The study by Álvarez-Hernández et al. (2025) underscores the diagnostic challenge of RMSF, noting that it can mimic other endemic febrile illnesses like dengue and COVID-19 in hospitalized children [1]. This highlights the importance of a meticulous history and physical assessment. While the study compares clinical profiles, the classic centripetal rash pattern with petechial evolution remains a cornerstone of clinical diagnosis and a critical point for nursing assessment and prompt reporting. A nurse must recognize this early, as delayed treatment with doxycycline is associated with significant mortality. Analysis of Correct and Incorrect Options **Correct Option:** The petechial rash beginning on wrists and ankles is the most characteristic finding for RMSF. This peripheral, centripetally-spreading, and often hemorrhagic rash directly reflects the underlying small-vessel vasculitis. **Incorrect Options:** - **Option 1: Koplik spots on the buccal mucosa.** This finding is pathognomonic for measles (rubeola). Koplik spots are small, bluish-white spots on a red background, appearing on the buccal mucosa opposite the molars, and they precede the characteristic maculopapular rash of measles. They are not associated with RMSF. - **Option 2: Vesicular rash starting on the trunk.** A vesicular rash that begins on the trunk and spreads to the face and extremities is characteristic of varicella (chickenpox). The lesions progress from macules to papules to vesicles and then crust over. This is a distinctly different morphology and distribution from the petechial rash of RMSF. - **Option 4: Erythema migrans with central clearing.** This is the hallmark rash of early localized Lyme disease, caused by Borrelia burgdorferi and transmitted by the Ixodes tick. It presents as an expanding, target-like lesion with central clearing at the site of the tick bite. While both Lyme disease and RMSF are tick-borne, their characteristic rashes are distinctly different. References (research sources) - [1]A Comparison of the Clinical and Epidemiological Profile of Rocky Mountain Spotted Fever with Dengue and COVID-19 in Hospitalized Children, Sonora, México, 2015-2022.Research articleÁlvarez-Hernández G, Rivera-Rosas CN, Calleja-López JRT, Álvarez-Meza JB, Candia-Plata MDC, Cruz-Loustaunau D, Alvídrez-Labrado A. (2025) · DOI: 10.3390/tropicalmed10010020 ## 임상 시나리오 RMSF Rash IdentificationRecognizing the hallmark petechial rash for early intervention Suspect Rocky Mountain Spotted Fever (RMSF) in a febrile patient with a history of tick exposure in an endemic area. The rash typically appears 2-5 days after fever onset. The classic rash begins as maculopapular eruptions on the wrists and ankles, spreading centripetally to the trunk. The key diagnostic feature is progression to petechiae (non-blanching spots) due to underlying vasculitis. CautionDo not wait for the petechial rash to develop to initiate treatment. Early empiric doxycycline is critical and should be started immediately upon clinical suspicion to reduce mortality, even in children. ## 핵심 개념 - **Rocky Mountain Spotted Fever (RMSF)** — A tick-borne bacterial infection caused by Rickettsia rickettsii, characterized by fever, headache, and a petechial rash starting on the wrists and ankles. - **Petechiae** — Small, pinpoint, non-blanching red or purple spots on the skin caused by capillary bleeding, a hallmark of vasculitic processes like RMSF. - **Rickettsia rickettsii** — The obligate intracellular bacterium that causes RMSF, transmitted by dog, wood, or lone star ticks, and infecting endothelial cells. - **Centripetal Rash Spread** — A rash pattern that begins on the extremities (wrists/ankles) and spreads inward toward the trunk, classic for RMSF. - **Vasculitis** — Inflammation of blood vessel walls, which in RMSF leads to increased vascular permeability and the characteristic petechial rash. ## 같은 주제 문제 - [A 7-year-old child is brought to the emergency department with a 3-day history of fever, h…](https://mymerci.kr/pages/nclex_q.php?qn_id=542289) - [A 10-year-old child presents to the emergency department with a 4-day history of fever, he…](https://mymerci.kr/pages/nclex_q.php?qn_id=542290) - [A 10-year-old child is diagnosed with Rocky Mountain spotted fever after developing a char…](https://mymerci.kr/pages/nclex_q.php?qn_id=542292) - [A nurse is caring for a 7-year-old child diagnosed with Rocky Mountain spotted fever (RMSF…](https://mymerci.kr/pages/nclex_q.php?qn_id=542293) - [A 10-year-old child is admitted to the pediatric unit with a diagnosis of Rocky Mountain s…](https://mymerci.kr/pages/nclex_q.php?qn_id=542294) --- More free questions: [기출문제](https://mymerci.kr/) _학습 참고용입니다. 실제 임상은 최신 지침과 소속 기관 프로토콜을 따르세요._