Patients with Ehrlichia infections, regardless of organism, typically present with fever, malaise, headache, body aches, and chills. Symptoms typically begin one to two weeks after a tick bite, at a median of nine days. It is important to collect history regarding travel to endemic areas and outdoor activities of patients with these non-specific flu-like symptoms during the summer months. Prompt recognition and treatment of ehrlichiosis and other tick-borne illnesses may improve outcomes. Other findings may include gastrointestinal symptoms, such as nausea, vomiting and diarrhea, and rash. The rash is more common in children and typically presents five days into illness as a maculopapular rash, petechiae, or diffuse erythema. Cough and respiratory symptoms are more common in adults than in children. Similar to rickettsial infections, central nervous system involvement can also occur in up to 20% of patients, including meningitis and meningoencephalitis.

In some patients, symptoms may progress to acute respiratory distress syndrome (ARDS) or a sepsis-like or shock-like presentation with cardiovascular instability and coagulopathy. However, overall mortality is much lower in ehrlichiosis than in rickettsial disease. The Centers for Disease Control and Prevention (CDC) reports mortality rates of 1% to 3%, since 2000, in patients who present for medical care of ehrlichiosis. Importantly, many patients may be infected with ehrlichiosis but not present for medical evaluation, and thus this may be an overestimate of mortality. Patients who are immunocompromised, elderly, or have received pretreatment with sulfonamide antibiotics are predisposed to more severe illness.[6][7][8][9]

Laboratory findings in ehrlichiosis may include leukopenia, thrombocytopenia, and mild to moderately elevated transaminases. Hyponatremia may also be a finding. In some cases, morulae may be present in the peripheral blood or other body fluids of a patient with ehrlichiosis. However, this is not considered a diagnostic of ehrlichiosis. Cerebrospinal leukocytosis and mildly elevated protein levels may also occur. In most centers, diagnosis of ehrlichiosis occurs via polymerase chain reaction (PCR), which is particularly useful in these infections given their predilection for infecting circulating leukocytes. Treatment with doxycycline can decrease the sensitivity of PCR, so samples should be collected before initiation of treatment if possible without significantly delaying therapy. Serology may also be an option; however, culture is not a routine test performed to diagnose ehrlichiosis.

Doxycycline is the preferred drug for the treatment of ehrlichiosis, as well as for rickettsial infection. There is no clinical data to support the use of alternative agents for ehrlichiosis, although in vitro studies suggest that rifampin may be an option. However, as there is no demonstrated clinical efficacy of rifampin in treating ehrlichiosis and as rifampin has no efficacy against rickettsial infections, which can be indistinguishable from ehrlichiosis in the early stages of illness, doxycycline remains the drug of choice. Patients with ehrlichiosis typically defervesce in 48 to 72 hours after initiation of doxycycline. Treatment courses are typically five to seven days, based on illness severity. Several clinical studies have demonstrated that tooth staining is a rare cosmetic complication of doxycycline at the doses and duration used to treat ehrlichiosis and rickettsial infections. Concerns regarding age and potential tooth staining should not delay treatment with doxycycline in children with suspected ehrlichiosis. There is currently no recommendation for post-tick bite prophylaxis against ehrlichiosis in endemic areas.[10][11]

• Bacterial sepsis  

• Endocarditis

• Hepatitis

• Influenza

• Kawasaki disease

• Leptospirosis

• Murine typhus

• Q fever

• Toxic shock syndrome

• Typhoid fever

When diagnosed and treated promptly, ehrlichiosis will generally respond well, symptomatic improvement within 24 to 48 hours. However, in those with additional health conditions, severe infection, or who experience a delay in treatment, the disease can be serious or even fatal; this is why empiric therapy of suspected ehrlichiosis should commence immediately, even before the finalizing of laboratory results.[12]

In rare instances, e.g., patients with a weak immune system (as can be the case with HIV or cancer), ehrlichiosis can lead to serious complications. These include:

• Brain conditions, including confusion, seizures, or coma
• Hemorrhage
• Heart failure
• Respiratory failure
• Kidney failure
• Septic shock

These complications may require additional treatment, including respiratory support, IV fluids, or kidney dialysis. Complications are more prevalent in the elderly or people with pre-existing health conditions.[13]

Patients with ehrlichiosis cannot pass the disease on to other humans, but the presence of an infected individual indicates the potential for others to contract tick-borne diseases. Therefore patients need to be taught the best practices for tick avoidance as well as tick control measures.[14]

There is no vaccine available for any of the Ehrlichia species. Avoidance of tick bites remains the mainstay of prevention, with the application of insect repellents, avoidance of high-risk areas, covering all exposed skin, and checking carefully for ticks after outdoor activities in endemic areas. As ehrlichiosis is not transmitted directly person-to-person, no isolation is needed.

The majority of patients with Ehrlichia infections present to the emergency department or the primary care provider/nurse practitioner. Because the symptoms and signs of Ehrlichia infection are not specific, it is essential to consult with an infectious disease expert early on. The infection can involve the skin, CNS, GI tract, and muscle or even present with shock. The Centers for Disease Control and Prevention (CDC) reports mortality rates of 1% to 3%, since 2000, in patients who present for medical care of ehrlichiosis. Importantly, many patients may be infected with ehrlichiosis but not present for medical evaluation, and thus this may be an overestimate of mortality. Patients who are immunocompromised, elderly, or have received pretreatment with sulfonamide antibiotics are predisposed to more severe illness

There is no vaccine available for any of the Ehrlichia species. Avoidance of tick bites remains the mainstay of prevention, with the application of insect repellents, avoidance of high-risk areas, covering all exposed skin, and checking carefully for ticks after outdoor activities in endemic areas. As ehrlichiosis is not transmitted directly person-to-person, no isolation is needed.[15][16]