RMSF in pregnancy can present without the classic rash or tick bite history. A 37-year-old pregnant woman was admitted to the hospital at 31 weeks gestation due to severe headaches and a fever that had been ongoing for 1 week. A few days prior to admission, she developed night sweats, chills, sweating, dyspnea and diarrhea.

Her symptoms began while travelling in Washington. She reported hiking outdoors but did not notice a rash or tick bite.

“This is the first case to our knowledge to report RMSF in pregnancy without a significant rash or tick history,” the authors state.

Initial misdiagnosis

The woman was treated for atypical HELLP syndrome, a life-threatening pregnancy complication usually considered to be a variant of preeclampsia and prescribed antibiotics.

However, 6 hours after starting the antibiotics, her symptoms worsened. She continued to have a fever and developed severe tachypnea, and tachycardia.

She was intubated and a cesarean section was performed.

RMSF in pregnancy confirmed

“The patient was started on doxycycline immediately after vancomycin was discontinued,” the authors state.

“RMSF became the presumed diagnosis due to the clinical criteria of headache, fever, and malaise, laboratory findings notable for thrombocytopenia, transaminitis, acutely worsening disease, and cerebrospinal fluid analysis consistent with aseptic meningitis,” the authors point out.

The patient’s symptoms improved on doxycycline and the infant was born healthy with no evidence of infection.

Treatment recommendations

The authors note, “Prompt and timely treatment with doxycycline significantly limits the morbidity and mortality of RMSF in both children and adults.”

Additionally, increasing evidence suggests that doxycycline can be prescribed safely in pregnancy.

“Given the potentially dire implications in pregnancy, providers in endemic areas should consider RMSF in the differential of atypical presentations in pregnant women and those with a fever of unknown origin.”

This case highlights that RMSF in pregnancy requires a high index of suspicion, even without classic signs like rash or known tick exposure.